csh (1)





NAME

       tcsh - C shell with file name completion and command line editing


SYNOPSIS

       tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
       tcsh -l


DESCRIPTION

       tcsh  is  an enhanced but completely compatible version of the Berkeley
       UNIX C shell, csh(1).  It is a command language interpreter usable both
       as an interactive login shell and a shell script command processor.  It
       includes a command-line editor  (see  The  command-line  editor),  pro-
       grammable  word  completion (see Completion and listing), spelling cor-
       rection (see Spelling correction), a  history  mechanism  (see  History
       substitution),  job  control  (see  Jobs) and a C-like syntax.  The NEW
       FEATURES section describes major  enhancements  of  tcsh  over  csh(1).
       Throughout  this  manual,  features  of  tcsh  not found in most csh(1)
       implementations (specifically, the 4.4BSD csh) are labeled with  `(+)',
       and features which are present in csh(1) but not usually documented are
       labeled with `(u)'.

   Argument list processing
       If the first argument (argument 0) to the shell is `-'  then  it  is  a
       login shell.  A login shell can be also specified by invoking the shell
       with the -l flag as the only argument.

       The rest of the flag arguments are interpreted as follows:

       -b  Forces a ``break'' from  option  processing,  causing  any  further
           shell arguments to be treated as non-option arguments.  The remain-
           ing arguments will not be interpreted as shell options.   This  may
           be used to pass options to a shell script without confusion or pos-
           sible subterfuge.  The shell will not  run  a  set-user  ID  script
           without this option.

       -c  Commands  are  read  from  the  following  argument  (which must be
           present, and must be a single  argument),  stored  in  the  command
           shell  variable  for  reference, and executed.  Any remaining argu-
           ments are placed in the argv shell variable.

       -d  The shell loads the directory stack from  ~/.cshdirs  as  described
           under Startup and shutdown, whether or not it is a login shell. (+)

       -Dname[=value]
           Sets the environment variable name to value. (Domain/OS only) (+)

       -e  The shell exits if any invoked  command  terminates  abnormally  or
           yields a non-zero exit status.

       -f  The shell ignores ~/.tcshrc, and thus starts faster.

       -F  The  shell  uses  fork(2)  instead  of vfork(2) to spawn processes.
           (Convex/OS only) (+)

       -i  The shell is interactive and prompts for its top-level input,  even
       -n  The shell parses commands but does not execute them.  This aids  in
           debugging shell scripts.

       -q  The shell accepts SIGQUIT (see Signal handling) and behaves when it
           is used under a debugger.  Job control is disabled. (u)

       -s  Command input is taken from the standard input.

       -t  The shell reads and executes a single line of input.  A `\' may  be
           used  to  escape  the  newline at the end of this line and continue
           onto another line.

       -v  Sets the verbose shell variable, so that command  input  is  echoed
           after history substitution.

       -x  Sets  the  echo shell variable, so that commands are echoed immedi-
           ately before execution.

       -V  Sets the verbose shell variable even before executing ~/.tcshrc.

       -X  Is to -x as -V is to -v.

       After processing of flag arguments, if arguments remain but none of the
       -c,  -i,  -s,  or -t options were given, the first argument is taken as
       the name of a file of commands, or ``script'',  to  be  executed.   The
       shell opens this file and saves its name for possible resubstitution by
       `$0'.  Because many systems use either the standard version 6  or  ver-
       sion  7  shells whose shell scripts are not compatible with this shell,
       the shell uses such a `standard' shell to execute a script whose  first
       character is not a `#', i.e., that does not start with a comment.

       Remaining arguments are placed in the argv shell variable.

   Startup and shutdown
       A  login  shell  begins  by  executing  commands  from the system files
       /etc/csh.cshrc and /etc/csh.login.   It  then  executes  commands  from
       files  in  the  user's  home  directory:  first  ~/.tcshrc  (+)  or, if
       ~/.tcshrc is not found, ~/.cshrc, then ~/.history (or the value of  the
       histfile shell variable), then ~/.login, and finally ~/.cshdirs (or the
       value of  the  dirsfile  shell  variable)  (+).   The  shell  may  read
       /etc/csh.login  before  instead  of  after /etc/csh.cshrc, and ~/.login
       before instead of after ~/.tcshrc or ~/.cshrc  and  ~/.history,  if  so
       compiled; see the version shell variable. (+)

       Non-login  shells read only /etc/csh.cshrc and ~/.tcshrc or ~/.cshrc on
       startup.

       For examples of startup  files,  please  consult  http://tcshrc.source-
       forge.net.

       Commands  like  stty(1)  and  tset(1),  which need be run only once per
       login, usually go in one's ~/.login file.  Users who need  to  use  the
       same  set  of  files with both csh(1) and tcsh can have only a ~/.cshrc
       which checks for the existence of the tcsh shell variable (q.v.) before
       using  tcsh-specific  commands,  or  can  have  both  a  ~/.cshrc and a
       ~/.tcshrc which sources (see the builtin command) ~/.cshrc.   The  rest
       of  this manual uses `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is
       One can log out by typing `^D' on an empty line, `logout' or `login' or
       via the shell's autologout mechanism (see the  autologout  shell  vari-
       able).  When a login shell terminates it sets the logout shell variable
       to `normal' or `automatic' as appropriate, then executes commands  from
       the  files  /etc/csh.logout  and  ~/.logout.  The shell may drop DTR on
       logout if so compiled; see the version shell variable.

       The names of the system login and logout files vary from system to sys-
       tem for compatibility with different csh(1) variants; see FILES.

   Editing
       We  first describe The command-line editor.  The Completion and listing
       and Spelling correction sections describe  two  sets  of  functionality
       that  are  implemented  as  editor commands but which deserve their own
       treatment.  Finally, Editor commands lists  and  describes  the  editor
       commands specific to the shell and their default bindings.

   The command-line editor (+)
       Command-line  input  can  be edited using key sequences much like those
       used in GNU Emacs or vi(1).  The editor is active only  when  the  edit
       shell  variable  is  set, which it is by default in interactive shells.
       The bindkey builtin can display and change key  bindings.   Emacs-style
       key  bindings are used by default (unless the shell was compiled other-
       wise; see the version shell variable), but bindkey can change  the  key
       bindings to vi-style bindings en masse.

       The  shell always binds the arrow keys (as defined in the TERMCAP envi-
       ronment variable) to

           down    down-history
           up      up-history
           left    backward-char
           right   forward-char

       unless doing so would alter another single-character binding.  One  can
       set  the  arrow  key escape sequences to the empty string with settc to
       prevent these bindings.  The ANSI/VT100 sequences for  arrow  keys  are
       always bound.

       Other  key  bindings are, for the most part, what Emacs and vi(1) users
       would expect and can easily be displayed by bindkey,  so  there  is  no
       need to list them here.  Likewise, bindkey can list the editor commands
       with a short description of each.

       Note that editor commands do not have the same notion of a ``word''  as
       does  the  shell.   The editor delimits words with any non-alphanumeric
       characters not in the shell variable wordchars, while the shell  recog-
       nizes  only whitespace and some of the characters with special meanings
       to it, listed under Lexical structure.

   Completion and listing (+)
       The shell is often able to complete words when given a unique abbrevia-
       tion.  Type part of a word (for example `ls /usr/lost') and hit the tab
       key to run the complete-word editor command.  The shell  completes  the
       filename  `/usr/lost'  to  `/usr/lost+found/', replacing the incomplete
       word with the complete word in the input buffer.   (Note  the  terminal
       `/';  completion  adds  a `/' to the end of completed directories and a
       text  pushes  the  rest  of  the  line to the right.  Completion in the
       middle of a word often results in leftover characters to the  right  of
       the cursor that need to be deleted.

       Commands  and  variables  can  be  completed in much the same way.  For
       example, typing `em[tab]' would complete `em' to `emacs' if emacs  were
       the  only  command  on your system beginning with `em'.  Completion can
       find a command in any directory in path or if given  a  full  pathname.
       Typing  `echo  $ar[tab]'  would  complete  `$ar' to `$argv' if no other
       variable began with `ar'.

       The shell parses the input buffer to determine  whether  the  word  you
       want  to  complete  should be completed as a filename, command or vari-
       able.  The first word in the buffer and the first word  following  `;',
       `|',  `|&',  `&&' or `||' is considered to be a command.  A word begin-
       ning with `$' is considered to be a variable.  Anything else is a file-
       name.  An empty line is `completed' as a filename.

       You  can  list the possible completions of a word at any time by typing
       `^D' to run the delete-char-or-list-or-eof editor command.   The  shell
       lists  the  possible  completions  using  the  ls-F builtin (q.v.)  and
       reprints the prompt and unfinished command line, for example:

           > ls /usr/l[^D]
           lbin/       lib/        local/      lost+found/
           > ls /usr/l

       If the autolist shell variable is set, the shell  lists  the  remaining
       choices (if any) whenever completion fails:

           > set autolist
           > nm /usr/lib/libt[tab]
           libtermcap.a@ libtermlib.a@
           > nm /usr/lib/libterm

       If autolist is set to `ambiguous', choices are listed only when comple-
       tion fails and adds no new characters to the word being completed.

       A filename to be completed can contain variables, your own  or  others'
       home  directories  abbreviated with `~' (see Filename substitution) and
       directory stack entries abbreviated with `=' (see Directory stack  sub-
       stitution).  For example,

           > ls ~k[^D]
           kahn    kas     kellogg
           > ls ~ke[tab]
           > ls ~kellogg/

       or

           > set local = /usr/local
           > ls $lo[tab]
           > ls $local/[^D]
           bin/ etc/ lib/ man/ src/
           > ls $local/

       Note  that  variables  can also be expanded explicitly with the expand-
       bindkey builtin command if so desired.

       The complete-word-fwd and complete-word-back editor commands (not bound
       to any keys by default) can be used to cycle up and  down  through  the
       list  of possible completions, replacing the current word with the next
       or previous word in the list.

       The shell variable fignore can be set to  a  list  of  suffixes  to  be
       ignored by completion.  Consider the following:

           > ls
           Makefile        condiments.h~   main.o          side.c
           README          main.c          meal            side.o
           condiments.h    main.c~
           > set fignore = (.o \~)
           > emacs ma[^D]
           main.c   main.c~  main.o
           > emacs ma[tab]
           > emacs main.c

       `main.c~'  and  `main.o'  are  ignored by completion (but not listing),
       because they end in suffixes in fignore.  Note that a `\' was needed in
       front  of  `~'  to  prevent it from being expanded to home as described
       under Filename substitution.  fignore is ignored if only one completion
       is possible.

       If  the  complete  shell  variable  is  set to `enhance', completion 1)
       ignores case and 2) considers periods, hyphens  and  underscores  (`.',
       `-'  and  `_')  to be word separators and hyphens and underscores to be
       equivalent.  If you had the following files

           comp.lang.c      comp.lang.perl   comp.std.c++
           comp.lang.c++    comp.std.c

       and typed `mail -f c.l.c[tab]', it  would  be  completed  to  `mail  -f
       comp.lang.c',  and  ^D  would  list  `comp.lang.c' and `comp.lang.c++'.
       `mail -f c..c++[^D]' would  list  `comp.lang.c++'  and  `comp.std.c++'.
       Typing `rm a--file[^D]' in the following directory

           A_silly_file    a-hyphenated-file    another_silly_file

       would  list  all  three  files, because case is ignored and hyphens and
       underscores are equivalent.  Periods, however, are  not  equivalent  to
       hyphens or underscores.

       Completion  and  listing are affected by several other shell variables:
       recexact can be set to complete on the shortest possible unique  match,
       even if more typing might result in a longer match:

           > ls
           fodder   foo      food     foonly
           > set recexact
           > rm fo[tab]

       just beeps, because `fo' could expand to `fod' or `foo', but if we type
       another `o',

       tion beep or not beep in a variety of situations, and nobeep can be set
       to  never  beep  at  all.   nostat  can be set to a list of directories
       and/or patterns  that  match  directories  to  prevent  the  completion
       mechanism  from  stat(2)ing those directories.  listmax and listmaxrows
       can be set to limit the number of items and  rows  (respectively)  that
       are listed without asking first.  recognize_only_executables can be set
       to make the shell list only executables when listing commands,  but  it
       is quite slow.

       Finally, the complete builtin command can be used to tell the shell how
       to complete words other than filenames, commands and  variables.   Com-
       pletion  and listing do not work on glob-patterns (see Filename substi-
       tution), but the list-glob  and  expand-glob  editor  commands  perform
       equivalent functions for glob-patterns.

   Spelling correction (+)
       The shell can sometimes correct the spelling of filenames, commands and
       variable names as well as completing and listing them.

       Individual words can be spelling-corrected with the  spell-word  editor
       command (usually bound to M-s and M-S) and the entire input buffer with
       spell-line (usually bound to M-$).  The correct shell variable  can  be
       set to `cmd' to correct the command name or `all' to correct the entire
       line each time return is typed, and autocorrect can be set  to  correct
       the word to be completed before each completion attempt.

       When  spelling correction is invoked in any of these ways and the shell
       thinks that any part of the command line is misspelled, it prompts with
       the corrected line:

           > set correct = cmd
           > lz /usr/bin
           CORRECT>ls /usr/bin (y|n|e|a)?

       One can answer `y' or space to execute the corrected line, `e' to leave
       the uncorrected command in the input buffer, `a' to abort  the  command
       as if `^C' had been hit, and anything else to execute the original line
       unchanged.

       Spelling correction recognizes user-defined completions (see  the  com-
       plete  builtin  command).   If  an input word in a position for which a
       completion is defined resembles a word in the completion list, spelling
       correction  registers  a  misspelling and suggests the latter word as a
       correction.  However, if the input word does not match any of the  pos-
       sible  completions for that position, spelling correction does not reg-
       ister a misspelling.

       Like completion, spelling correction works anywhere in the line,  push-
       ing  the rest of the line to the right and possibly leaving extra char-
       acters to the right of the cursor.

       Beware: spelling correction is not  guaranteed  to  work  the  way  one
       intends,  and  is  provided mostly as an experimental feature.  Sugges-
       tions and improvements are welcome.

   Editor commands (+)
       `bindkey' lists  key  bindings  and  `bindkey  -l'  lists  and  briefly
       venience.

       complete-word (tab)
               Completes a word as described under Completion and listing.

       complete-word-back (not bound)
               Like complete-word-fwd, but steps up from the end of the  list.

       complete-word-fwd (not bound)
               Replaces  the  current  word with the first word in the list of
               possible completions.  May be repeated to step down through the
               list.   At the end of the list, beeps and reverts to the incom-
               plete word.

       complete-word-raw (^X-tab)
               Like complete-word, but ignores user-defined completions.

       copy-prev-word (M-^_)
               Copies the previous word in the current  line  into  the  input
               buffer.  See also insert-last-word.

       dabbrev-expand (M-/)
               Expands  the  current word to the most recent preceding one for
               which the current is a leading substring, wrapping  around  the
               history  list  (once)  if  necessary.  Repeating dabbrev-expand
               without any intervening typing changes  to  the  next  previous
               word etc., skipping identical matches much like history-search-
               backward does.

       delete-char (not bound)
               Deletes the character under the cursor.  See also  delete-char-
               or-list-or-eof.

       delete-char-or-eof (not bound)
               Does  delete-char  if  there is a character under the cursor or
               end-of-file on an empty line.  See also delete-char-or-list-or-
               eof.

       delete-char-or-list (not bound)
               Does  delete-char  if  there is a character under the cursor or
               list-choices at the end of the line.  See also  delete-char-or-
               list-or-eof.

       delete-char-or-list-or-eof (^D)
               Does  delete-char  if  there  is  a character under the cursor,
               list-choices at the end of the line or end-of-file on an  empty
               line.  See also those three commands, each of which does only a
               single action, and delete-char-or-eof, delete-char-or-list  and
               list-or-eof,  each  of  which  does  a different two out of the
               three.

       down-history (down-arrow, ^N)
               Like up-history, but steps down, stopping at the original input
               line.

       end-of-file (not bound)
               Signals  an  end  of file, causing the shell to exit unless the
               Expands  the glob-pattern to the left of the cursor.  See File-
               name substitution.

       expand-line (not bound)
               Like expand-history, but expands history substitutions in  each
               word in the input buffer,

       expand-variables (^X-$)
               Expands  the  variable to the left of the cursor.  See Variable
               substitution.

       history-search-backward (M-p, M-P)
               Searches backwards through  the  history  list  for  a  command
               beginning  with  the current contents of the input buffer up to
               the cursor and copies it into the  input  buffer.   The  search
               string  may  be a glob-pattern (see Filename substitution) con-
               taining `*', `?', `[]' or `{}'.   up-history  and  down-history
               will  proceed  from  the appropriate point in the history list.
               Emacs mode only.  See also history-search-forward and i-search-
               back.

       history-search-forward (M-n, M-N)
               Like history-search-backward, but searches forward.

       i-search-back (not bound)
               Searches  backward  like  history-search-backward,  copies  the
               first match into the input buffer with the cursor positioned at
               the  end of the pattern, and prompts with `bck: ' and the first
               match.  Additional  characters  may  be  typed  to  extend  the
               search,  i-search-back  may be typed to continue searching with
               the same pattern, wrapping around the history  list  if  neces-
               sary,  (i-search-back  must  be bound to a single character for
               this to work) or one of the following special characters may be
               typed:

                   ^W      Appends  the  rest  of the word under the cursor to
                           the search pattern.
                   delete (or any character bound to backward-delete-char)
                           Undoes the effect of the last character  typed  and
                           deletes  a  character  from  the  search pattern if
                           appropriate.
                   ^G      If the previous search was successful,  aborts  the
                           entire  search.  If not, goes back to the last suc-
                           cessful search.
                   escape  Ends the search, leaving the current  line  in  the
                           input buffer.

               Any other character not bound to self-insert-command terminates
               the search, leaving the current line in the input  buffer,  and
               is then interpreted as normal input.  In particular, a carriage
               return causes the current line  to  be  executed.   Emacs  mode
               only.  See also i-search-fwd and history-search-backward.

       i-search-fwd (not bound)
               Like i-search-back, but searches forward.

       insert-last-word (M-_)
               Like list-choices, but ignores user-defined completions.

       list-glob (^X-g, ^X-G)
               Lists (via the ls-F builtin) matches to the  glob-pattern  (see
               Filename substitution) to the left of the cursor.

       list-or-eof (not bound)
               Does  list-choices  or  end-of-file on an empty line.  See also
               delete-char-or-list-or-eof.

       magic-space (not bound)
               Expands history substitutions in the current line, like expand-
               history,  and  appends  a space.  magic-space is designed to be
               bound to the space bar, but is not bound by default.

       normalize-command (^X-?)
               Searches for the current word in PATH  and,  if  it  is  found,
               replaces  it  with  the  full  path to the executable.  Special
               characters are quoted.  Aliases are  expanded  and  quoted  but
               commands  within  aliases are not.  This command is useful with
               commands that take commands as arguments, e.g., `dbx'  and  `sh
               -x'.

       normalize-path (^X-n, ^X-N)
               Expands  the  current word as described under the `expand' set-
               ting of the symlinks shell variable.

       overwrite-mode (unbound)
               Toggles between input and overwrite modes.

       run-fg-editor (M-^Z)
               Saves the current input line and looks for a stopped job with a
               name  equal  to the last component of the file name part of the
               EDITOR or VISUAL environment variables, or, if neither is  set,
               `ed'  or  `vi'.   If such a job is found, it is restarted as if
               `fg %job' had been typed.  This is  used  to  toggle  back  and
               forth between an editor and the shell easily.  Some people bind
               this command to `^Z' so they can do this even more easily.

       run-help (M-h, M-H)
               Searches for documentation on the current  command,  using  the
               same  notion  of  `current command' as the completion routines,
               and prints it.  There is no way to use  a  pager;  run-help  is
               designed  for  short help files.  If the special alias helpcom-
               mand is defined, it is run with the  command  name  as  a  sole
               argument.   Else,  documentation should be in a file named com-
               mand.help, command.1, command.6, command.8  or  command,  which
               should  be  in one of the directories listed in the HPATH envi-
               ronment variable.  If there is more than one help file only the
               first is printed.

       self-insert-command (text characters)
               In  insert mode (the default), inserts the typed character into
               the input line after the character under the cursor.  In  over-
               write  mode,  replaces  the character under the cursor with the
               typed character.  The input mode is normally preserved  between
               lines,  but the inputmode shell variable can be set to `insert'
               bound to undefined-key unless bound to another command.

       spell-line (M-$)
               Attempts to correct the spelling of  each  word  in  the  input
               buffer,  like spell-word, but ignores words whose first charac-
               ter is one of `-', `!', `^' or `%', or which contain  `\',  `*'
               or  `?', to avoid problems with switches, substitutions and the
               like.  See Spelling correction.

       spell-word (M-s, M-S)
               Attempts to  correct  the  spelling  of  the  current  word  as
               described  under Spelling correction.  Checks each component of
               a word which appears to be a pathname.

       toggle-literal-history (M-r, M-R)
               Expands or  `unexpands'  history  substitutions  in  the  input
               buffer.  See also expand-history and the autoexpand shell vari-
               able.

       undefined-key (any unbound key)
               Beeps.

       up-history (up-arrow, ^P)
               Copies the previous entry in the history list  into  the  input
               buffer.  If histlit is set, uses the literal form of the entry.
               May be repeated to step up through the history  list,  stopping
               at the top.

       vi-search-back (?)
               Prompts  with `?' for a search string (which may be a glob-pat-
               tern, as with history-search-backward),  searches  for  it  and
               copies it into the input buffer.  The bell rings if no match is
               found.  Hitting return ends the  search  and  leaves  the  last
               match  in the input buffer.  Hitting escape ends the search and
               executes the match.  vi mode only.

       vi-search-fwd (/)
               Like vi-search-back, but searches forward.

       which-command (M-?)
               Does a which (see the description of the  builtin  command)  on
               the first word of the input buffer.

   Lexical structure
       The  shell  splits input lines into words at blanks and tabs.  The spe-
       cial characters `&', `|', `;', `<', `>', `(', and `)' and  the  doubled
       characters `&&', `||', `<<' and `>>' are always separate words, whether
       or not they are surrounded by whitespace.

       When the shell's input is not a terminal, the character `#' is taken to
       begin  a  comment.  Each `#' and the rest of the input line on which it
       appears is discarded before further parsing.

       A special character (including a blank or tab) may  be  prevented  from
       having  its special meaning, and possibly made part of another word, by
       preceding it with a backslash (`\') or enclosing it  in  single  (`''),
       double  (`"')  or  backward  (``') quotes.  When not otherwise quoted a
       defined  prevents  substitution of the alias.  The usual way of quoting
       an alias is to precede it with a backslash.)  History  substitution  is
       prevented by backslashes but not by single quotes.  Strings quoted with
       double or backward quotes undergo  Variable  substitution  and  Command
       substitution, but other substitutions are prevented.

       Text  inside  single or double quotes becomes a single word (or part of
       one).  Metacharacters in these strings, including blanks and  tabs,  do
       not form separate words.  Only in one special case (see Command substi-
       tution below) can a double-quoted string yield parts of more  than  one
       word;  single-quoted  strings  never  do.  Backward quotes are special:
       they signal Command substitution (q.v.), which may result in more  than
       one word.

       Quoting  complex strings, particularly strings which themselves contain
       quoting characters, can be confusing.  Remember that quotes need not be
       used  as  they  are in human writing!  It may be easier to quote not an
       entire string, but only those parts of the string which  need  quoting,
       using different types of quoting to do so if appropriate.

       The  backslash_quote  shell  variable  (q.v.)  can be set to make back-
       slashes always quote `\', `'', and `"'.   (+)  This  may  make  complex
       quoting tasks easier, but it can cause syntax errors in csh(1) scripts.

   Substitutions
       We now describe the various transformations the shell performs  on  the
       input  in  the  order in which they occur.  We note in passing the data
       structures involved and the commands and variables which  affect  them.
       Remember  that  substitutions  can be prevented by quoting as described
       under Lexical structure.

   History substitution
       Each command, or ``event'', input from the terminal  is  saved  in  the
       history  list.   The  previous command is always saved, and the history
       shell variable can be set to a number to save that many commands.   The
       histdup  shell variable can be set to not save duplicate events or con-
       secutive duplicate events.

       Saved commands are numbered sequentially from 1 and  stamped  with  the
       time.   It  is not usually necessary to use event numbers, but the cur-
       rent event number can be made part of the prompt by placing an  `!'  in
       the prompt shell variable.

       The  shell  actually saves history in expanded and literal (unexpanded)
       forms.  If the histlit shell variable is set, commands that display and
       store history use the literal form.

       The  history  builtin  command  can print, store in a file, restore and
       clear the history list at any time, and the savehist and histfile shell
       variables  can be can be set to store the history list automatically on
       logout and restore it on login.

       History substitutions introduce words from the history  list  into  the
       input  stream, making it easy to repeat commands, repeat arguments of a
       previous command in the current command, or fix  spelling  mistakes  in
       the  previous  command  with  little typing and a high degree of confi-
       dence.
       contains a history substitution is printed before it is executed.

       A history substitution may have an ``event specification'', which indi-
       cates  the  event  from  which words are to be taken, a ``word designa-
       tor'', which selects particular words from the chosen event,  and/or  a
       ``modifier'', which manipulates the selected words.

       An event specification can be

           n       A number, referring to a particular event
           -n      An  offset,  referring  to  the  event n before the current
                   event
           #       The current  event.   This  should  be  used  carefully  in
                   csh(1), where there is no check for recursion.  tcsh allows
                   10 levels of recursion.  (+)
           !       The previous event (equivalent to `-1')
           s       The most recent event whose  first  word  begins  with  the
                   string s
           ?s?     The  most  recent  event  which contains the string s.  The
                   second `?' can be omitted if it is immediately followed  by
                   a newline.

       For example, consider this bit of someone's history list:

            9  8:30    nroff -man wumpus.man
           10  8:31    cp wumpus.man wumpus.man.old
           11  8:36    vi wumpus.man
           12  8:37    diff wumpus.man.old wumpus.man

       The  commands  are shown with their event numbers and time stamps.  The
       current event, which we haven't typed in yet, is event 13.   `!11'  and
       `!-2'  refer to event 11.  `!!' refers to the previous event, 12.  `!!'
       can be abbreviated `!' if it is  followed  by  `:'  (`:'  is  described
       below).   `!n' refers to event 9, which begins with `n'.  `!?old?' also
       refers to event 12, which contains `old'.  Without word designators  or
       modifiers  history  references simply expand to the entire event, so we
       might type `!cp' to redo the copy command or `!!|more'  if  the  `diff'
       output scrolled off the top of the screen.

       History  references  may  be  insulated  from the surrounding text with
       braces if necessary.  For example, `!vdoc' would  look  for  a  command
       beginning  with  `vdoc',  and,  in  this  example,  not  find  one, but
       `!{v}doc' would expand unambiguously to `vi  wumpus.mandoc'.   Even  in
       braces, history substitutions do not nest.

       (+) While csh(1) expands, for example, `!3d' to event 3 with the letter
       `d' appended to it, tcsh expands it to the last  event  beginning  with
       `3d';  only  completely numeric arguments are treated as event numbers.
       This makes it possible to recall events  beginning  with  numbers.   To
       expand `!3d' as in csh(1) say `!\3d'.

       To  select words from an event we can follow the event specification by
       a `:' and a designator for the desired words.  The words  of  an  input
       line are numbered from 0, the first (usually command) word being 0, the
       second word (first argument) being 1, etc.  The basic word  designators
       are:

           x*      Equivalent to `x-$'
           x-      Equivalent to `x*', but omitting the last word (`$')

       Selected words are inserted into the command line separated  by  single
       blanks.   For example, the `diff' command in the previous example might
       have been typed as `diff !!:1.old !!:1' (using `:1' to select the first
       argument  from  the previous event) or `diff !-2:2 !-2:1' to select and
       swap the arguments from the `cp' command.  If we didn't care about  the
       order  of  the `diff' we might have said `diff !-2:1-2' or simply `diff
       !-2:*'.  The `cp'  command  might  have  been  written  `cp  wumpus.man
       !#:1.old',  using `#' to refer to the current event.  `!n:- hurkle.man'
       would reuse the first two words from the `nroff' command to say  `nroff
       -man hurkle.man'.

       The `:' separating the event specification from the word designator can
       be omitted if the argument selector begins with a `^', `$', `*', `%' or
       `-'.   For  example,  our  `diff' command might have been `diff !!^.old
       !!^' or, equivalently, `diff !!$.old !!$'.  However, if `!!' is  abbre-
       viated `!', an argument selector beginning with `-' will be interpreted
       as an event specification.

       A history reference may have a word designator but no event  specifica-
       tion.   It then references the previous command.  Continuing our `diff'
       example, we could have said simply `diff !^.old  !^'  or,  to  get  the
       arguments in the opposite order, just `diff !*'.

       The  word  or  words  in  a history reference can be edited, or ``modi-
       fied'', by following it with one or more modifiers, each preceded by  a
       `:':

           h       Remove a trailing pathname component, leaving the head.
           t       Remove all leading pathname components, leaving the tail.
           r       Remove  a filename extension `.xxx', leaving the root name.
           e       Remove all but the extension.
           u       Uppercase the first lowercase letter.
           l       Lowercase the first uppercase letter.
           s/l/r/  Substitute l for r.  l is simply a string  like  r,  not  a
                   regular  expression as in the eponymous ed(1) command.  Any
                   character may be used as the delimiter in place of  `/';  a
                   `\' can be used to quote the delimiter inside l and r.  The
                   character `&' in the r is replaced by l;  `\'  also  quotes
                   `&'.  If l is empty (``''), the l from a previous substitu-
                   tion or the s from a previous `?s?' event specification  is
                   used.  The trailing delimiter may be omitted if it is imme-
                   diately followed by a newline.
           &       Repeat the previous substitution.
           g       Apply the following modifier once to each word.
           a (+)   Apply the following modifier as many times as possible to a
                   single  word.   `a' and `g' can be used together to apply a
                   modifier globally.  In the  current  implementation,  using
                   the  `a' and `s' modifiers together can lead to an infinite
                   loop.  For example, `:as/f/ff/' will never terminate.  This
                   behavior might change in the future.
           p       Print the new command line but do not execute it.
           q       Quote  the  substituted words, preventing further substitu-
                   tions.
           x       Like q, but break into words at blanks, tabs and  newlines.

       password"  rot'  with  `!:s/rot/root' to correct the spelling of `root'
       (but see Spelling correction for a different approach).

       There is a special abbreviation for substitutions.  `^', when it is the
       first  character  on  an  input line, is equivalent to `!:s^'.  Thus we
       might have said `^rot^root' to make the spelling correction in the pre-
       vious  example.   This  is the only history substitution which does not
       explicitly begin with `!'.

       (+) In csh as such, only one modifier may be applied to each history or
       variable expansion.  In tcsh, more than one may be used, for example

           % mv wumpus.man /usr/man/man1/wumpus.1
           % man !$:t:r
           man wumpus

       In csh, the result would be `wumpus.1:r'.  A substitution followed by a
       colon may need to be insulated from it with braces:

           > mv a.out /usr/games/wumpus
           > setenv PATH !$:h:$PATH
           Bad ! modifier: $.
           > setenv PATH !{-2$:h}:$PATH
           setenv PATH /usr/games:/bin:/usr/bin:.

       The first attempt would succeed in csh but fails in tcsh, because  tcsh
       expects another modifier after the second colon rather than `$'.

       Finally,  history can be accessed through the editor as well as through
       the substitutions just described.  The up- and  down-history,  history-
       search-backward  and  -forward,  i-search-back and -fwd, vi-search-back
       and -fwd, copy-prev-word and insert-last-word  editor  commands  search
       for  events  in  the  history list and copy them into the input buffer.
       The toggle-literal-history editor command switches between the expanded
       and literal forms of history lines in the input buffer.  expand-history
       and expand-line expand history substitutions in the current word and in
       the entire input buffer respectively.

   Alias substitution
       The  shell  maintains  a  list  of  aliases which can be set, unset and
       printed by the alias and unalias commands.  After  a  command  line  is
       parsed  into simple commands (see Commands) the first word of each com-
       mand, left-to-right, is checked to see if it has an alias.  If so,  the
       first  word  is replaced by the alias.  If the alias contains a history
       reference, it undergoes History substitution (q.v.) as though the orig-
       inal  command were the previous input line.  If the alias does not con-
       tain a history reference, the argument list is left untouched.

       Thus if the alias for `ls' were `ls -l' the  command  `ls  /usr'  would
       become  `ls -l /usr', the argument list here being undisturbed.  If the
       alias for `lookup' were `grep !^ /etc/passwd' then `lookup bill'  would
       become  `grep  bill  /etc/passwd'.   Aliases  can  be used to introduce
       parser metasyntax.  For example, `alias print 'pr \!* | lpr'' defines a
       ``command'' (`print') which pr(1)s its arguments to the line printer.

       Alias  substitution is repeated until the first word of the command has
       no alias.  If an alias substitution does not change the first word  (as
       tains  its  own  list  of ``environment'' variables.  These can be dis-
       played and changed with printenv, setenv and unsetenv.

       (+) Variables may be made read-only with  `set  -r'  (q.v.)   Read-only
       variables  may not be modified or unset; attempting to do so will cause
       an error.  Once made read-only, a variable cannot be made writable,  so
       `set  -r' should be used with caution.  Environment variables cannot be
       made read-only.

       Some variables are set  by  the  shell  or  referred  to  by  it.   For
       instance,  the  argv variable is an image of the shell's argument list,
       and words of this variable's value are referred  to  in  special  ways.
       Some  of  the variables referred to by the shell are toggles; the shell
       does not care what their value is, only whether they are  set  or  not.
       For  instance,  the  verbose  variable is a toggle which causes command
       input to be echoed.  The -v command line  option  sets  this  variable.
       Special  shell  variables  lists all variables which are referred to by
       the shell.

       Other operations treat variables numerically.  The `@' command  permits
       numeric calculations to be performed and the result assigned to a vari-
       able.  Variable values are, however, always  represented  as  (zero  or
       more) strings.  For the purposes of numeric operations, the null string
       is considered to be zero, and the second and subsequent words of multi-
       word values are ignored.

       After  the input line is aliased and parsed, and before each command is
       executed, variable substitution is performed keyed by  `$'  characters.
       This  expansion can be prevented by preceding the `$' with a `\' except
       within `"'s where it always occurs, and  within  `''s  where  it  never
       occurs.   Strings quoted by ``' are interpreted later (see Command sub-
       stitution below) so `$' substitution does not occur there until  later,
       if  at  all.  A `$' is passed unchanged if followed by a blank, tab, or
       end-of-line.

       Input/output redirections are recognized before variable expansion, and
       are  variable  expanded  separately.   Otherwise,  the command name and
       entire argument list are expanded together.  It is  thus  possible  for
       the  first  (command)  word  (to  this point) to generate more than one
       word, the first of which becomes the command  name,  and  the  rest  of
       which become arguments.

       Unless  enclosed in `"' or given the `:q' modifier the results of vari-
       able substitution may eventually be command and  filename  substituted.
       Within  `"',  a variable whose value consists of multiple words expands
       to a (portion of a) single word, with the words of the variable's value
       separated  by blanks.  When the `:q' modifier is applied to a substitu-
       tion the variable will expand to multiple words with  each  word  sepa-
       rated  by  a blank and quoted to prevent later command or filename sub-
       stitution.

       The following metasequences are provided for introducing variable  val-
       ues into the shell input.  Except as noted, it is an error to reference
       a variable which is not set.

       $name
       ${name} Substitutes the words of the value of variable name, each sepa-
               Substitutes  only  the  selected  words from the value of name.
               The selector is subjected to `$' substitution and  may  consist
               of  a  single  number  or  two numbers separated by a `-'.  The
               first word of a variable's value is numbered `1'.  If the first
               number  of  a range is omitted it defaults to `1'.  If the last
               member of a range is omitted  it  defaults  to  `$#name'.   The
               selector `*' selects all words.  It is not an error for a range
               to be empty if the second argument is omitted or in range.
       $0      Substitutes the name of the file from which  command  input  is
               being read.  An error occurs if the name is not known.
       $number
       ${number}
               Equivalent to `$argv[number]'.
       $*      Equivalent to `$argv', which is equivalent to `$argv[*]'.

       The  `:'  modifiers  described  under  History substitution, except for
       `:p', can be applied to the substitutions above.  More than one may  be
       used.   (+)  Braces  may  be needed to insulate a variable substitution
       from a literal colon just as with History substitution (q.v.); any mod-
       ifiers must appear within the braces.

       The following substitutions can not be modified with `:' modifiers.

       $?name
       ${?name}
               Substitutes the string `1' if name is set, `0' if it is not.
       $?0     Substitutes  `1' if the current input filename is known, `0' if
               it is not.  Always `0' in interactive shells.
       $#name
       ${#name}
               Substitutes the number of words in name.
       $#      Equivalent to `$#argv'.  (+)
       $%name
       ${%name}
               Substitutes the number of characters in name.  (+)
       $%number
       ${%number}
               Substitutes the number of characters in $argv[number].  (+)
       $?      Equivalent to `$status'.  (+)
       $$      Substitutes the (decimal) process number of the (parent) shell.
       $!      Substitutes the (decimal) process number of the last background
               process started by this shell.  (+)
       $_      Substitutes the command line of the last command executed.  (+)
       $<      Substitutes  a  line  from  the standard input, with no further
               interpretation thereafter.  It can be used  to  read  from  the
               keyboard in a shell script.  (+) While csh always quotes $<, as
               if it were equivalent to `$<:q', tcsh does  not.   Furthermore,
               when  tcsh  is waiting for a line to be typed the user may type
               an interrupt to interrupt the sequence into which the  line  is
               to be substituted, but csh does not allow this.

       The  editor  command expand-variables, normally bound to `^X-$', can be
       used to interactively expand individual variables.

   Command, filename and directory stack substitution
       The remaining substitutions are applied selectively to the arguments of
       builtin  commands.   This  means that portions of expressions which are
       able and command substituted and put in place of the original string.

       Command substitutions inside double  quotes  (`"')  retain  blanks  and
       tabs; only newlines force new words.  The single final newline does not
       force a new word in any case.  It is thus possible for a  command  sub-
       stitution  to  yield only part of a word, even if the command outputs a
       complete line.

   Filename substitution
       If a word contains any of the characters `*', `?', `[' or `{' or begins
       with  the  character  `~'  it is a candidate for filename substitution,
       also known as ``globbing''.  This word is then regarded  as  a  pattern
       (``glob-pattern''),  and replaced with an alphabetically sorted list of
       file names which match the pattern.

       In matching filenames, the character `.' at the beginning of a filename
       or  immediately  following  a `/', as well as the character `/' must be
       matched explicitly.  The character `*' matches any  string  of  charac-
       ters,  including the null string.  The character `?' matches any single
       character.  The sequence `[...]' matches  any  one  of  the  characters
       enclosed.   Within  `[...]',  a  pair  of  characters  separated by `-'
       matches any character lexically between the two.

       (+) Some glob-patterns can be negated: The  sequence  `[^...]'  matches
       any  single  character not specified by the characters and/or ranges of
       characters in the braces.

       An entire glob-pattern can also be negated with `^':

           > echo *
           bang crash crunch ouch
           > echo ^cr*
           bang ouch

       Glob-patterns which do not use `?', `*', or `[]' or which use  `{}'  or
       `~' (below) are not negated correctly.

       The  metanotation  `a{b,c,d}e' is a shorthand for `abe ace ade'.  Left-
       to-right order is preserved: `/usr/source/s1/{oldls,ls}.c'  expands  to
       `/usr/source/s1/oldls.c  /usr/source/s1/ls.c'.   The results of matches
       are  sorted  separately  at  a  low  level  to  preserve  this   order:
       `../{memo,*box}'  might expand to `../memo ../box ../mbox'.  (Note that
       `memo' was not sorted with the results of matching `*box'.)  It is  not
       an  error  when this construct expands to files which do not exist, but
       it is possible to get an error from a command  to  which  the  expanded
       list  is  passed.  This construct may be nested.  As a special case the
       words `{', `}' and `{}' are passed undisturbed.

       The character `~' at the beginning of a filename refers to home  direc-
       tories.   Standing  alone,  i.e., `~', it expands to the invoker's home
       directory as reflected in the value of the home shell  variable.   When
       followed by a name consisting of letters, digits and `-' characters the
       shell searches for a user with that name  and  substitutes  their  home
       directory;  thus `~ken' might expand to `/usr/ken' and `~ken/chmach' to
       `/usr/ken/chmach'.  If the character `~' is  followed  by  a  character
       other  than  a letter or `/' or appears elsewhere than at the beginning
       of a word, it is left undisturbed.   A  command  like  `setenv  MANPATH
       unchanged rather than causing an error.

       The noglob shell variable can be set to prevent filename  substitution,
       and  the  expand-glob  editor command, normally bound to `^X-*', can be
       used to interactively expand individual filename substitutions.

   Directory stack substitution (+)
       The directory stack is a list of directories, numbered from zero,  used
       by  the  pushd, popd and dirs builtin commands (q.v.).  dirs can print,
       store in a file, restore and clear the directory stack at any time, and
       the  savedirs  and  dirsfile  shell  variables  can be set to store the
       directory stack automatically on logout and restore it on  login.   The
       dirstack  shell variable can be examined to see the directory stack and
       set to put arbitrary directories into the directory stack.

       The character `=' followed by one or more digits expands to an entry in
       the  directory stack.  The special case `=-' expands to the last direc-
       tory in the stack.  For example,

           > dirs -v
           0       /usr/bin
           1       /usr/spool/uucp
           2       /usr/accts/sys
           > echo =1
           /usr/spool/uucp
           > echo =0/calendar
           /usr/bin/calendar
           > echo =-
           /usr/accts/sys

       The noglob and nonomatch shell variables  and  the  expand-glob  editor
       command apply to directory stack as well as filename substitutions.

   Other substitutions (+)
       There   are  several  more  transformations  involving  filenames,  not
       strictly related to the above but mentioned here for completeness.  Any
       filename  may  be  expanded  to  a full path when the symlinks variable
       (q.v.) is set to `expand'.  Quoting prevents this  expansion,  and  the
       normalize-path editor command does it on demand.  The normalize-command
       editor command expands commands in PATH  into  full  paths  on  demand.
       Finally,  cd  and  pushd  interpret  `-'  as  the old working directory
       (equivalent to the shell variable owd).  This is not a substitution  at
       all,  but  an abbreviation recognized by only those commands.  Nonethe-
       less, it too can be prevented by quoting.

   Commands
       The next three sections describe how the shell  executes  commands  and
       deals with their input and output.

   Simple commands, pipelines and sequences
       A  simple  command is a sequence of words, the first of which specifies
       the command to be executed.  A series of simple commands joined by  `|'
       characters  forms a pipeline.  The output of each command in a pipeline
       is connected to the input of the next.

       Simple commands and pipelines may be joined into  sequences  with  `;',
       and  will be executed sequentially.  Commands and pipelines can also be

   Builtin and non-builtin command execution
       Builtin  commands are executed within the shell.  If any component of a
       pipeline except the last is a builtin command, the pipeline is executed
       in a subshell.

       Parenthesized commands are always executed in a subshell.

           (cd; pwd); pwd

       thus  prints  the  home directory, leaving you where you were (printing
       this after the home directory), while

           cd; pwd

       leaves you in the home  directory.   Parenthesized  commands  are  most
       often used to prevent cd from affecting the current shell.

       When  a command to be executed is found not to be a builtin command the
       shell attempts to execute the command via execve(2).  Each word in  the
       variable  path  names  a directory in which the shell will look for the
       command.  If it is given neither a -c nor a -t option, the shell hashes
       the  names  in these directories into an internal table so that it will
       try an execve(2) in only a directory where there is a possibility  that
       the command resides there.  This greatly speeds command location when a
       large number of directories are present in the search  path.   If  this
       mechanism has been turned off (via unhash), if the shell was given a -c
       or -t argument or in any case for  each  directory  component  of  path
       which  does  not  begin  with a `/', the shell concatenates the current
       working directory with the given command name to form a path name of  a
       file which it then attempts to execute.

       If  the  file  has  execute permissions but is not an executable to the
       system (i.e., it is neither an executable  binary  nor  a  script  that
       specifies  its interpreter), then it is assumed to be a file containing
       shell commands and a new shell is spawned to read it.  The  shell  spe-
       cial  alias  may  be set to specify an interpreter other than the shell
       itself.

       On systems which do not understand the `#!' script interpreter  conven-
       tion  the  shell  may  be compiled to emulate it; see the version shell
       variable.  If so, the shell checks the first line of the file to see if
       it  is of the form `#!interpreter arg ...'.  If it is, the shell starts
       interpreter with the given args and feeds the file to  it  on  standard
       input.

   Input/output
       The  standard  input and standard output of a command may be redirected
       with the following syntax:

       < name  Open file name (which is first variable, command  and  filename
               expanded) as the standard input.
       << word Read  the  shell input up to a line which is identical to word.
               word is not subjected to variable, filename or command  substi-
               tution, and each input line is compared to word before any sub-
               stitutions are done on this input line.  Unless a quoting  `\',
               `"',  `'  or ``' appears in word variable and command substitu-
               tion is performed on the intervening  lines,  allowing  `\'  to
               The file name is used as standard output.  If the file does not
               exist then it is created; if the file exists, it is  truncated,
               its previous contents being lost.

               If  the shell variable noclobber is set, then the file must not
               exist or be a character  special  file  (e.g.,  a  terminal  or
               `/dev/null')  or an error results.  This helps prevent acciden-
               tal destruction of files.  In this case the `!'  forms  can  be
               used to suppress this check.

               The  forms  involving  `&' route the diagnostic output into the
               specified file  as  well  as  the  standard  output.   name  is
               expanded in the same way as `<' input filenames are.
       >> name
       >>& name
       >>! name
       >>&! name
               Like  `>', but appends output to the end of name.  If the shell
               variable noclobber is set, then it is an error for the file not
               to exist, unless one of the `!' forms is given.

       A  command  receives  the environment in which the shell was invoked as
       modified by the input-output parameters and the presence of the command
       in  a pipeline.  Thus, unlike some previous shells, commands run from a
       file of shell commands have no access to the text of  the  commands  by
       default;  rather they receive the original standard input of the shell.
       The `<<' mechanism should be used to present inline data.  This permits
       shell command scripts to function as components of pipelines and allows
       the shell to block read its input.   Note  that  the  default  standard
       input  for  a command run detached is not the empty file /dev/null, but
       the original standard input of the shell.  If this is a terminal and if
       the  process  attempts to read from the terminal, then the process will
       block and the user will be notified (see Jobs).

       Diagnostic output may be directed through a pipe with the standard out-
       put.  Simply use the form `|&' rather than just `|'.

       The  shell  cannot  presently  redirect  diagnostic output without also
       redirecting standard output, but `(command  >  output-file)  >&  error-
       file'  is often an acceptable workaround.  Either output-file or error-
       file may be `/dev/tty' to send output to the terminal.

   Features
       Having described how the shell accepts,  parses  and  executes  command
       lines, we now turn to a variety of its useful features.

   Control flow
       The  shell  contains a number of commands which can be used to regulate
       the flow of control in command files (shell scripts)  and  (in  limited
       but  useful  ways)  from terminal input.  These commands all operate by
       forcing the shell to reread or skip in its input and, due to the imple-
       mentation, restrict the placement of some of the commands.

       The  foreach, switch, and while statements, as well as the if-then-else
       form of the if statement, require that the major keywords appear  in  a
       single simple command on an input line as shown below.

       its own separate syntax.

   Logical, arithmetical and comparison operators
       These operators are similar to those of C and have the same precedence.
       They include

           ||  &&  |  ^  &  ==  !=  =~  !~  <=  >=
           <  > <<  >>  +  -  *  /  %  !  ~  (  )

       Here the precedence increases to the right, `==' `!='  `=~'  and  `!~',
       `<='  `>='  `<'  and  `>',  `<<' and `>>', `+' and `-', `*' `/' and `%'
       being, in groups, at the same level.  The `==' `!=' `=~' and `!~' oper-
       ators  compare  their  arguments as strings; all others operate on num-
       bers.  The operators `=~' and `!~' are like `!=' and `=='  except  that
       the  right  hand  side  is  a  glob-pattern (see Filename substitution)
       against which the left hand operand is matched.  This reduces the  need
       for use of the switch builtin command in shell scripts when all that is
       really needed is pattern matching.

       Strings which begin with `0' are considered  octal  numbers.   Null  or
       missing  arguments  are considered `0'.  The results of all expressions
       are strings, which represent decimal numbers.  It is important to  note
       that  no  two  components of an expression can appear in the same word;
       except when adjacent to components of expressions which  are  syntacti-
       cally  significant  to the parser (`&' `|' `<' `>' `(' `)') they should
       be surrounded by spaces.

   Command exit status
       Commands can be executed in expressions and their exit status  returned
       by enclosing them in braces (`{}').  Remember that the braces should be
       separated from the words of the command by spaces.  Command  executions
       succeed, returning true, i.e., `1', if the command exits with status 0,
       otherwise they fail, returning false, i.e., `0'.  If more detailed sta-
       tus information is required then the command should be executed outside
       of an expression and the status shell variable examined.

   File inquiry operators
       Some of these operators perform true/false tests on files  and  related
       objects.  They are of the form -op file, where op is one of

           r   Read access
           w   Write access
           x   Execute access
           X   Executable  in the path or shell builtin, e.g., `-X ls' and `-X
               ls-F' are generally true, but `-X /bin/ls' is not (+)
           e   Existence
           o   Ownership
           z   Zero size
           s   Non-zero size (+)
           f   Plain file
           d   Directory
           l   Symbolic link (+) *
           b   Block special file (+)
           c   Character special file (+)
           p   Named pipe (fifo) (+) *
           S   Socket special file (+) *
           u   Set-user-ID bit is set (+)

       file  is command and filename expanded and then tested to see if it has
       the specified relationship to the real user.  If file does not exist or
       is  inaccessible  or, for the operators indicated by `*', if the speci-
       fied file type does not exist on the current system, then all enquiries
       return false, i.e., `0'.

       These  operators may be combined for conciseness: `-xy file' is equiva-
       lent to `-x file && -y file'.  (+) For example, `-fx' is true  (returns
       `1') for plain executable files, but not for directories.

       L may be used in a multiple-operator test to apply subsequent operators
       to a symbolic link rather than to the file to which  the  link  points.
       For  example, `-lLo' is true for links owned by the invoking user.  Lr,
       Lw and Lx are always true for links and false for non-links.  L  has  a
       different  meaning  when it is the last operator in a multiple-operator
       test; see below.

       It is possible but not useful, and  sometimes  misleading,  to  combine
       operators  which  expect file to be a file with operators which do not,
       (e.g., X and t).  Following L with a non-file operator can lead to par-
       ticularly strange results.

       Other  operators  return  other information, i.e., not just `0' or `1'.
       (+) They have the same format as before; op may be one of

           A       Last file access time, as the number of seconds  since  the
                   epoch
           A:      Like A, but in timestamp format, e.g., `Fri May 14 16:36:10
                   1993'
           M       Last file modification time
           M:      Like M, but in timestamp format
           C       Last inode modification time
           C:      Like C, but in timestamp format
           D       Device number
           I       Inode number
           F       Composite file identifier, in the form device:inode
           L       The name of the file pointed to by a symbolic link
           N       Number of (hard) links
           P       Permissions, in octal, without leading zero
           P:      Like P, with leading zero
           Pmode   Equivalent to `-P file & mode', e.g., `-P22  file'  returns
                   `22'  if  file  is  writable by group and other, `20' if by
                   group only, and `0' if by neither
           Pmode:  Like Pmode:, with leading zero
           U       Numeric userid
           U:      Username, or the numeric userid if the username is unknown
           G       Numeric groupid
           G:      Groupname, or the  numeric  groupid  if  the  groupname  is
                   unknown
           Z       Size, in bytes

       Only one of these operators may appear in a multiple-operator test, and
       it must be the last.  Note that L has a different meaning at the end of
       and  elsewhere  in  a  multiple-operator  test.  Because `0' is a valid
       return value for many of these operators, they do not return  `0'  when
       they fail: most return `-1', and F returns `:'.


   Jobs
       The  shell  associates  a  job with each pipeline.  It keeps a table of
       current jobs, printed by the jobs command, and assigns them small inte-
       ger  numbers.  When a job is started asynchronously with `&', the shell
       prints a line which looks like

           [1] 1234

       indicating that the job which was started asynchronously was job number
       1 and had one (top-level) process, whose process id was 1234.

       If  you are running a job and wish to do something else you may hit the
       suspend key (usually `^Z'), which sends a STOP signal  to  the  current
       job.  The shell will then normally indicate that the job has been `Sus-
       pended' and print another prompt.  If the listjobs  shell  variable  is
       set,  all  jobs  will be listed like the jobs builtin command; if it is
       set to `long' the listing will be in long format, like `jobs -l'.   You
       can  then manipulate the state of the suspended job.  You can put it in
       the ``background'' with the bg command or run some other  commands  and
       eventually  bring  the  job back into the ``foreground'' with fg.  (See
       also the run-fg-editor editor command.)  A `^Z'  takes  effect  immedi-
       ately  and is like an interrupt in that pending output and unread input
       are discarded when it is typed.  The wait builtin  command  causes  the
       shell to wait for all background jobs to complete.

       The  `^]' key sends a delayed suspend signal, which does not generate a
       STOP signal until a program attempts to read(2) it, to the current job.
       This  can  usefully be typed ahead when you have prepared some commands
       for a job which you wish to stop after it has read them.  The `^Y'  key
       performs  this function in csh(1); in tcsh, `^Y' is an editing command.
       (+)

       A job being run in the background stops if it tries to  read  from  the
       terminal.   Background jobs are normally allowed to produce output, but
       this can be disabled by giving the command `stty tostop'.  If  you  set
       this  tty  option, then background jobs will stop when they try to pro-
       duce output like they do when they try to read input.

       There are several ways to refer to jobs in the  shell.   The  character
       `%'  introduces  a job name.  If you wish to refer to job number 1, you
       can name it as `%1'.  Just naming a job brings it  to  the  foreground;
       thus  `%1' is a synonym for `fg %1', bringing job 1 back into the fore-
       ground.  Similarly, saying `%1 &' resumes job 1 in the background, just
       like  `bg %1'.  A job can also be named by an unambiguous prefix of the
       string typed in to start it: `%ex' would normally restart  a  suspended
       ex(1)  job,  if there were only one suspended job whose name began with
       the string `ex'.  It is also possible to say `%?string'  to  specify  a
       job whose text contains string, if there is only one such job.

       The shell maintains a notion of the current and previous jobs.  In out-
       put pertaining to jobs, the current job is marked with a  `+'  and  the
       previous  job with a `-'.  The abbreviations `%+', `%', and (by analogy
       with the syntax of the history mechanism) `%%' all refer to the current
       job, and `%-' refers to the previous job.

       The job control mechanism requires that the stty(1) option `new' be set
       is done so that it does not otherwise disturb your work.  If,  however,
       you  set  the  shell variable notify, the shell will notify you immedi-
       ately of changes of status in background jobs.  There is also  a  shell
       command  notify which marks a single process so that its status changes
       will be immediately reported.  By default notify marks the current pro-
       cess; simply say `notify' after starting a background job to mark it.

       When  you  try  to  leave the shell while jobs are stopped, you will be
       warned that `You have stopped jobs.' You may use the  jobs  command  to
       see  what  they  are.  If you do this or immediately try to exit again,
       the shell will not warn you a second time, and the suspended jobs  will
       be terminated.

   Automatic, periodic and timed events (+)
       There are various ways to run commands and take other actions automati-
       cally at various times in the ``life cycle'' of the  shell.   They  are
       summarized  here, and described in detail under the appropriate Builtin
       commands, Special shell variables and Special aliases.

       The sched builtin command puts commands in a scheduled-event  list,  to
       be executed by the shell at a given time.

       The  beepcmd,  cwdcmd,  periodic,  precmd,  postcmd, and jobcmd Special
       aliases can be set, respectively, to execute commands  when  the  shell
       wants  to ring the bell, when the working directory changes, every tpe-
       riod minutes, before each prompt, before each  command  gets  executed,
       after  each  command  gets  executed,  and  when a job is started or is
       brought into the foreground.

       The autologout shell variable can be set to log out or lock  the  shell
       after a given number of minutes of inactivity.

       The  mail shell variable can be set to check for new mail periodically.

       The printexitvalue shell variable can be set to print the  exit  status
       of commands which exit with a status other than zero.

       The  rmstar  shell  variable can be set to ask the user, when `rm *' is
       typed, if that is really what was meant.

       The time shell variable can be set to execute the time builtin  command
       after the completion of any process that takes more than a given number
       of CPU seconds.

       The watch and who shell variables can be set to  report  when  selected
       users log in or out, and the log builtin command reports on those users
       at any time.

   Native Language System support (+)
       The shell is eight bit clean (if so compiled;  see  the  version  shell
       variable)  and  thus  supports  character sets needing this capability.
       NLS support differs depending on whether or not the shell was  compiled
       to  use  the  system's NLS (again, see version).  In either case, 7-bit
       ASCII is the default for character classification (e.g., which  charac-
       ters  are  printable)  and  sorting,  and changing the LANG or LC_CTYPE
       environment variables causes a check  for  possible  changes  in  these
       respects.

       In addition, with both real and simulated NLS, all printable characters
       in  the  range  \200-\377,  i.e.,  those that have M-char bindings, are
       automatically rebound to self-insert-command.  The corresponding  bind-
       ing for the escape-char sequence, if any, is left alone.  These charac-
       ters are not rebound if the NOREBIND environment variable is set.  This
       may  be  useful  for  the  simulated  NLS or a primitive real NLS which
       assumes full ISO 8859-1.  Otherwise, all M-char bindings in  the  range
       \240-\377  are  effectively  undone.  Explicitly rebinding the relevant
       keys with bindkey is of course still possible.

       Unknown characters (i.e., those that are neither printable nor  control
       characters) are printed in the format \nnn.  If the tty is not in 8 bit
       mode, other 8 bit characters are printed by converting  them  to  ASCII
       and  using  standout mode.  The shell never changes the 7/8 bit mode of
       the tty and tracks user-initiated changes of 7/8 bit mode.   NLS  users
       (or,  for  that  matter,  those who want to use a meta key) may need to
       explicitly set the tty in 8 bit mode through  the  appropriate  stty(1)
       command in, e.g., the ~/.login file.

   OS variant support (+)
       A  number  of  new builtin commands are provided to support features in
       particular operating systems.  All  are  described  in  detail  in  the
       Builtin commands section.

       On  systems  that  support  TCF  (aix-ibm370,  aix-ps2),  getspath  and
       setspath get and set the system execution path, getxvers  and  setxvers
       get  and  set the experimental version prefix and migrate migrates pro-
       cesses between sites.  The jobs builtin prints the site on  which  each
       job is executing.

       Under  Domain/OS,  inlib  adds shared libraries to the current environ-
       ment, rootnode changes the rootnode and ver changes the systype.

       Under Mach, setpath is equivalent to Mach's setpath(1).

       Under Masscomp/RTU and Harris CX/UX, universe sets the universe.

       Under Harris CX/UX, ucb or att runs a command under the specified  uni-
       verse.

       Under Convex/OS, warp prints or sets the universe.

       The  VENDOR, OSTYPE and MACHTYPE environment variables indicate respec-
       tively the vendor, operating system and  machine  type  (microprocessor
       class  or  machine model) of the system on which the shell thinks it is
       running.  These are particularly useful when sharing one's home  direc-
       tory between several types of machines; one can, for example,

           set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)

       in  one's ~/.login and put executables compiled for each machine in the
       appropriate directory.

       The version shell variable indicates what options were chosen when  the
       shell was compiled.

       inherited from its parent.

       In  shell scripts, the shell's handling of interrupt and terminate sig-
       nals can be controlled with onintr, and its handling of hangups can  be
       controlled with hup and nohup.

       The  shell  exits on a hangup (see also the logout shell variable).  By
       default, the shell's children do too, but the shell does not send  them
       a hangup when it exits.  hup arranges for the shell to send a hangup to
       a child when it exits, and nohup sets a child to ignore hangups.

   Terminal management (+)
       The shell uses  three  different  sets  of  terminal  (``tty'')  modes:
       `edit',  used  when editing, `quote', used when quoting literal charac-
       ters, and `execute', used when executing  commands.   The  shell  holds
       some settings in each mode constant, so commands which leave the tty in
       a confused state do not interfere  with  the  shell.   The  shell  also
       matches  changes  in the speed and padding of the tty.  The list of tty
       modes that are kept constant can be  examined  and  modified  with  the
       setty  builtin.  Note that although the editor uses CBREAK mode (or its
       equivalent), it takes typed-ahead characters anyway.

       The echotc, settc and telltc commands can be  used  to  manipulate  and
       debug terminal capabilities from the command line.

       On  systems  that  support  SIGWINCH  or SIGWINDOW, the shell adapts to
       window resizing automatically and  adjusts  the  environment  variables
       LINES and COLUMNS if set.  If the environment variable TERMCAP contains
       li# and co# fields, the shell adjusts them to reflect  the  new  window
       size.


REFERENCE

       The  next sections of this manual describe all of the available Builtin
       commands, Special aliases and Special shell variables.

   Builtin commands
       %job    A synonym for the fg builtin command.

       %job &  A synonym for the bg builtin command.

       :       Does nothing, successfully.

       @
       @ name = expr
       @ name[index] = expr
       @ name++|--
       @ name[index]++|--
               The first form prints the values of all shell variables.

               The second form assigns the value of expr to name.   The  third
               form  assigns  the  value  of expr to the index'th component of
               name; both name and its index'th component must already  exist.

               expr  may  contain  the  operators `*', `+', etc., as in C.  If
               expr contains `<', `>', `&' or `' then at least  that  part  of
               expr  must be placed within `()'.  Note that the syntax of expr
               has nothing to do with that described under Expressions.
               Without  arguments,  prints all aliases.  With name, prints the
               alias for name.  With name and wordlist,  assigns  wordlist  as
               the  alias  of  name.  wordlist is command and filename substi-
               tuted.  name may not be `alias' or  `unalias'.   See  also  the
               unalias builtin command.

       alloc   Shows  the  amount of dynamic memory acquired, broken down into
               used and free memory.  With an argument  shows  the  number  of
               free  and  used  blocks  in each size category.  The categories
               start at size 8 and double at each step.  This command's output
               may  vary  across  system types, because systems other than the
               VAX may use a different memory allocator.

       bg [%job ...]
               Puts the specified jobs (or,  without  arguments,  the  current
               job)  into  the  background,  continuing each if it is stopped.
               job may be a number, a string, `', `%', `+' or `-' as described
               under Jobs.

       bindkey [-l|-d|-e|-v|-u] (+)
       bindkey [-a] [-b] [-k] [-r] [--] key (+)
       bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
               Without  options,  the  first form lists all bound keys and the
               editor command to which each is bound, the  second  form  lists
               the  editor  command  to  which key is bound and the third form
               binds the editor command command to key.  Options include:

               -l  Lists all editor commands and a short description of  each.
               -d  Binds  all  keys  to  the standard bindings for the default
                   editor.
               -e  Binds all keys to the standard GNU Emacs-like bindings.
               -v  Binds all keys to the standard vi(1)-like bindings.
               -a  Lists or changes key-bindings in the alternative  key  map.
                   This is the key map used in vi command mode.
               -b  key  is interpreted as a control character written ^charac-
                   ter (e.g., `^A') or C-character (e.g., `C-A'), a meta char-
                   acter  written  M-character  (e.g.,  `M-A'), a function key
                   written F-string (e.g., `F-string'), or an extended  prefix
                   key written X-character (e.g., `X-A').
               -k  key  is interpreted as a symbolic arrow key name, which may
                   be one of `down', `up', `left' or `right'.
               -r  Removes key's binding.  Be careful: `bindkey -r'  does  not
                   bind key to self-insert-command (q.v.), it unbinds key com-
                   pletely.
               -c  command is interpreted as a  builtin  or  external  command
                   instead of an editor command.
               -s  command  is taken as a literal string and treated as termi-
                   nal input when key is typed.  Bound  keys  in  command  are
                   themselves reinterpreted, and this continues for ten levels
                   of interpretation.
               --  Forces a break from option processing, so the next word  is
                   taken as key even if it begins with '-'.
               -u (or any invalid option)
                   Prints a usage message.

               key  may  be  a  single character or a string.  If a command is
               bound to a string, the first character of the string  is  bound

                   \a      Bell
                   \b      Backspace
                   \e      Escape
                   \f      Form feed
                   \n      Newline
                   \r      Carriage return
                   \t      Horizontal tab
                   \v      Vertical tab
                   \nnn    The ASCII character corresponding to the octal num-
                           ber nnn

               `\' nullifies the special meaning of the  following  character,
               if it has any, notably `\' and `^'.

       break   Causes execution to resume after the end of the nearest enclos-
               ing foreach or while.  The remaining commands  on  the  current
               line  are  executed.   Multi-level  breaks are thus possible by
               writing them all on one line.

       breaksw Causes a break from a switch, resuming after the endsw.

       builtins (+)
               Prints the names of all builtin commands.

       bye (+) A synonym for the logout builtin command.   Available  only  if
               the shell was so compiled; see the version shell variable.

       case label:
               A label in a switch statement as discussed below.

       cd [-p] [-l] [-n|-v] [name]
               If  a  directory  name  is  given,  changes the shell's working
               directory to name.  If not, changes to home.  If name is `-' it
               is  interpreted  as  the  previous working directory (see Other
               substitutions).  (+) If name is not a subdirectory of the  cur-
               rent  directory  (and  does not begin with `/', `./' or `../'),
               each component of the variable cdpath is checked to see  if  it
               has  a  subdirectory name.  Finally, if all else fails but name
               is a shell variable whose value begins with `/', then  this  is
               tried to see if it is a directory.

               With -p, prints the final directory stack, just like dirs.  The
               -l, -n and -v flags have the same effect on cd as on dirs,  and
               they imply -p.  (+)

               See also the implicitcd shell variable.

       chdir   A synonym for the cd builtin command.

       complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
               Without  arguments, lists all completions.  With command, lists
               completions for command.  With command and word  etc.,  defines
               completions.

               command may be a full command name or a glob-pattern (see File-
               name substitution).  It can begin with  `-'  to  indicate  that
                   C   Like  c,  but includes pattern when completing the cur-
                       rent word.
                   n   Next-word completion.  pattern is a glob-pattern  which
                       must  match  the  beginning of the previous word on the
                       command line.
                   N   Like n, but must match the beginning of  the  word  two
                       before the current word.
                   p   Position-dependent  completion.   pattern  is a numeric
                       range, with the same syntax used to index  shell  vari-
                       ables, which must include the current word.

               list,  the list of possible completions, may be one of the fol-
               lowing:

                   a       Aliases
                   b       Bindings (editor commands)
                   c       Commands (builtin or external commands)
                   C       External commands which  begin  with  the  supplied
                           path prefix
                   d       Directories
                   D       Directories which begin with the supplied path pre-
                           fix
                   e       Environment variables
                   f       Filenames
                   F       Filenames which begin with the supplied path prefix
                   g       Groupnames
                   j       Jobs
                   l       Limits
                   n       Nothing
                   s       Shell variables
                   S       Signals
                   t       Plain (``text'') files
                   T       Plain  (``text'')  files  which begin with the sup-
                           plied path prefix
                   v       Any variables
                   u       Usernames
                   x       Like n, but  prints  select  when  list-choices  is
                           used.
                   X       Completions
                   $var    Words from the variable var
                   (...)   Words from the given list
                   `...`   Words from the output of command

               select  is an optional glob-pattern.  If given, words from only
               list that match select are considered  and  the  fignore  shell
               variable  is  ignored.   The last three types of completion may
               not have a select pattern, and x uses select as an  explanatory
               message when the list-choices editor command is used.

               suffix  is  a  single  character to be appended to a successful
               completion.  If null, no character is appended.  If omitted (in
               which  case  the fourth delimiter can also be omitted), a slash
               is appended to directories and a space to other words.

               Now for some examples.  Some commands take only directories  as
               arguments, so there's no point completing plain files.

                   > co[^D]
                   > compress

               This completion completes commands (words in position 0, `p/0')
               which begin with `co' (thus matching `co*') to `compress'  (the
               only  word  in  the list).  The leading `-' indicates that this
               completion is to be used with only ambiguous commands.

                   > complete find 'n/-user/u/'

               is an example of n-type completion.  Any word following  `find'
               and immediately following `-user' is completed from the list of
               users.

                   > complete cc 'c/-I/d/'

               demonstrates c-type completion.  Any word  following  `cc'  and
               beginning  with  `-I' is completed as a directory.  `-I' is not
               taken as part of the directory because we used lowercase c.

               Different lists are useful with different commands.

                   > complete alias 'p/1/a/'
                   > complete man 'p/*/c/'
                   > complete set 'p/1/s/'
                   > complete true 'p/1/x:Truth has no options./'

               These complete words following `alias' with aliases, `man' with
               commands,  and `set' with shell variables.  `true' doesn't have
               any options, so x does nothing when completion is attempted and
               prints  `Truth  has  no  options.'  when completion choices are
               listed.

               Note that the man example, and several  other  examples  below,
               could just as well have used 'c/*' or 'n/*' as 'p/*'.

               Words  can be completed from a variable evaluated at completion
               time,

                   > complete ftp 'p/1/$hostnames/'
                   > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu)
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu
                   > ftp [^C]
                   >  set  hostnames  =   (rtfm.mit.edu   tesla.ee.cornell.edu
                   uunet.uu.net)
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net

               or from a command run at completion time:

                   > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
                   > kill -9 [^D]
                   23113 23377 23380 23406 23429 23529 23530 PID

               Note  that the complete command does not itself quote its argu-
               ments, so the braces, space and `$' in  `{print  $1}'  must  be
               Because completions are evaluated from left to  right,  if  the
               next-word completion were specified first it would always match
               and the positional completion would never be executed.  This is
               a common mistake when defining a completion.

               The  select  pattern  is useful when a command takes files with
               only particular forms as arguments.  For example,

                   > complete cc 'p/*/f:*.[cao]/'

               completes `cc' arguments to files ending in only `.c', `.a', or
               `.o'.  select can also exclude files, using negation of a glob-
               pattern as described under Filename  substitution.   One  might
               use

                   > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'

               to  exclude  precious  source  code  from  `rm' completion.  Of
               course, one could still type excluded names manually  or  over-
               ride  the  completion  mechanism using the complete-word-raw or
               list-choices-raw editor commands (q.v.).

               The `C', `D', `F' and `T' lists are like `c', `d', `f' and  `t'
               respectively,  but  they use the select argument in a different
               way: to restrict completion to files beginning with a  particu-
               lar path prefix.  For example, the Elm mail program uses `=' as
               an abbreviation for one's mail directory.  One might use

                   > complete elm c@=@F:$HOME/Mail/@

               to complete `elm -f =' as if it were `elm  -f  ~/Mail/'.   Note
               that  we  used  `@'  instead of `/' to avoid confusion with the
               select argument, and we used `$HOME'  instead  of  `~'  because
               home  directory  substitution  works at only the beginning of a
               word.

               suffix is used to add a nonstandard suffix (not  space  or  `/'
               for directories) to completed words.

                   > complete finger 'c/*@/$hostnames/' 'p/1/u/@'

               completes arguments to `finger' from the list of users, appends
               an `@', and then completes after the `@' from  the  `hostnames'
               variable.   Note  again  the order in which the completions are
               specified.

               Finally, here's a complex example for inspiration:

                   > complete find \
                   īn/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
                   īn/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
                   īn/-group/g/' 'n/-fstype/(nfs 4.2)/' \
                   īn/-type/(b c d f l p s)/' \
                   īc/-/(name newer cpio ncpio exec ok user \
                   group fstype type atime ctime depth inum \
                   ls mtime nogroup nouser perm print prune \
                   size xdev)/' \

               otherwise completed to a directory.  Whew.

               Remember  that  programmed  completions are ignored if the word
               being completed is a tilde substitution (beginning with `~') or
               a  variable  (beginning with `$').  complete is an experimental
               feature, and the syntax may change in future  versions  of  the
               shell.  See also the uncomplete builtin command.

       continue
               Continues  execution of the nearest enclosing while or foreach.
               The rest of the commands on the current line are executed.

       default:
               Labels the default case in a switch statement.  It should  come
               after all case labels.

       dirs [-l] [-n|-v]
       dirs -S|-L [filename] (+)
       dirs -c (+)
               The  first  form  prints  the  directory stack.  The top of the
               stack is at the left and the first directory in  the  stack  is
               the  current  directory.  With -l, `~' or `~name' in the output
               is expanded explicitly to home or  the  pathname  of  the  home
               directory  for  user  name.   (+)  With -n, entries are wrapped
               before they reach the edge of the screen.  (+) With -v, entries
               are  printed  one  per line, preceded by their stack positions.
               (+) If more than one of -n or -v is given, -v takes precedence.
               -p is accepted but does nothing.

               With  -S, the second form saves the directory stack to filename
               as a series of cd and  pushd  commands.   With  -L,  the  shell
               sources  filename,  which  is presumably a directory stack file
               saved by the -S option or the savedirs  mechanism.   In  either
               case,  dirsfile is used if filename is not given and ~/.cshdirs
               is used if dirsfile is unset.

               Note that login shells  do  the  equivalent  of  `dirs  -L'  on
               startup  and,  if  savedirs  is  set, `dirs -S' before exiting.
               Because only ~/.tcshrc is normally sourced  before  ~/.cshdirs,
               dirsfile should be set in ~/.tcshrc rather than ~/.login.

               The last form clears the directory stack.

       echo [-n] word ...
               Writes  each  word to the shell's standard output, separated by
               spaces and terminated with a  newline.   The  echo_style  shell
               variable  may  be  set to emulate (or not) the flags and escape
               sequences of the BSD and/or System  V  versions  of  echo;  see
               echo(1).

       echotc [-sv] arg ... (+)
               Exercises  the  terminal capabilities (see termcap(5)) in args.
               For example, 'echotc home' sends the cursor to the  home  posi-
               tion,  'echotc  cm  3  10' sends it to column 3 and row 10, and
               'echotc ts 0; echo "This is a test."; echotc fs'  prints  "This
               is a test."  in the status line.


               Termcap strings may contain wildcards which will not echo  cor-
               rectly.   One  should  use  double  quotes when setting a shell
               variable to a terminal capability string, as in  the  following
               example that places the date in the status line:

                   > set tosl="`echotc ts 0`"
                   > set frsl="`echotc fs`"
                   > echo -n "$tosl";date; echo -n "$frsl"

               With  -s,  nonexistent  capabilities  return  the  empty string
               rather than causing an error.  With -v, messages are verbose.

       else
       end
       endif
       endsw   See the description of  the  foreach,  if,  switch,  and  while
               statements below.

       eval arg ...
               Treats  the  arguments  as  input to the shell and executes the
               resulting command(s) in the context of the current shell.  This
               is  usually used to execute commands generated as the result of
               command or variable substitution, because parsing occurs before
               these substitutions.  See tset(1) for a sample use of eval.

       exec command
               Executes the specified command in place of the current shell.

       exit [expr]
               The shell exits either with the value of the specified expr (an
               expression, as described under Expressions) or,  without  expr,
               with the value of the status variable.

       fg [%job ...]
               Brings  the  specified jobs (or, without arguments, the current
               job) into the foreground, continuing each  if  it  is  stopped.
               job may be a number, a string, `', `%', `+' or `-' as described
               under Jobs.  See also the run-fg-editor editor command.

       filetest -op file ... (+)
               Applies op (which is a file inquiry operator as described under
               File inquiry operators) to each file and returns the results as
               a space-separated list.

       foreach name (wordlist)
       ...
       end     Successively sets the variable name to each member of  wordlist
               and  executes the sequence of commands between this command and
               the matching end.  (Both foreach and end must appear  alone  on
               separate  lines.)   The builtin command continue may be used to
               continue the loop prematurely and the builtin command break  to
               terminate  it  prematurely.  When this command is read from the
               terminal, the loop is read once prompting with `foreach? '  (or
               prompt2)  before  any  statements in the loop are executed.  If
               you make a mistake typing in a loop at the terminal you can rub
               it out.
               delimited by null characters in the output.   Useful  for  pro-
               grams  which wish to use the shell to filename expand a list of
               words.

       goto word
               word is filename and command-substituted to yield a  string  of
               the  form `label'.  The shell rewinds its input as much as pos-
               sible, searches for a line of the form `label:', possibly  pre-
               ceded  by  blanks  or  tabs, and continues execution after that
               line.

       hashstat
               Prints a statistics line indicating how effective the  internal
               hash table has been at locating commands (and avoiding exec's).
               An exec is attempted for each component of the path  where  the
               hash  function  indicates a possible hit, and in each component
               which does not begin with a `/'.

               On machines without vfork(2), prints only the number  and  size
               of hash buckets.

       history [-hTr] [n]
       history -S|-L|-M [filename] (+)
       history -c (+)
               The  first  form  prints the history event list.  If n is given
               only the n most recent events are printed or saved.   With  -h,
               the  history list is printed without leading numbers.  If -T is
               specified, timestamps are printed also in comment form.   (This
               can be used to produce files suitable for loading with 'history
               -L' or 'source -h'.)  With -r, the order of  printing  is  most
               recent first rather than oldest first.

               With  -S,  the  second form saves the history list to filename.
               If the first word of the savehist shell variable is  set  to  a
               number,  at most that many lines are saved.  If the second word
               of savehist is set to `merge', the history list is merged  with
               the  existing history file instead of replacing it (if there is
               one) and sorted by time stamp.  (+) Merging is intended for  an
               environment  like  the  X  Window System with several shells in
               simultaneous use.  Currently it succeeds only when  the  shells
               quit nicely one after another.

               With -L, the shell appends filename, which is presumably a his-
               tory list saved by the -S option or the savehist mechanism,  to
               the  history list.  -M is like -L, but the contents of filename
               are merged into the history list and sorted by  timestamp.   In
               either  case,  histfile  is  used  if filename is not given and
               ~/.history is used if  histfile  is  unset.   `history  -L'  is
               exactly  like  'source  -h'  except  that it does not require a
               filename.

               Note that login shells do the equivalent  of  `history  -L'  on
               startup  and,  if savehist is set, `history -S' before exiting.
               Because only ~/.tcshrc is normally sourced  before  ~/.history,
               histfile should be set in ~/.tcshrc rather than ~/.login.

               If  histlit  is  set, the first and second forms print and save
               (allowed in only a shell script), causes the shell to exit on a
               hangup  for  the remainder of the script.  See also Signal han-
               dling and the nohup builtin command.

       if (expr) command
               If expr (an expression, as described under Expressions)  evalu-
               ates  true, then command is executed.  Variable substitution on
               command happens early, at the same time it does for the rest of
               the  if  command.   command  must  be  a simple command, not an
               alias, a pipeline, a command list or  a  parenthesized  command
               list,  but  it  may  have  arguments.  Input/output redirection
               occurs even if expr is false and command is thus not  executed;
               this is a bug.

       if (expr) then
       ...
       else if (expr2) then
       ...
       else
       ...
       endif   If  the  specified  expr is true then the commands to the first
               else are executed; otherwise if expr2 is true then the commands
               to  the  second  else are executed, etc.  Any number of else-if
               pairs are possible; only one endif is needed.  The else part is
               likewise  optional.   (The  words else and endif must appear at
               the beginning of input lines; the if must appear alone  on  its
               input line or after an else.)

       inlib shared-library ... (+)
               Adds  each shared-library to the current environment.  There is
               no way to remove a shared library.  (Domain/OS only)

       jobs [-l]
               Lists the active jobs.  With -l, lists process IDs in  addition
               to  the normal information.  On TCF systems, prints the site on
               which each job is executing.

       kill [-s signal] %job|pid ...
       kill -l The first and second forms sends the specified signal  (or,  if
               none  is  given,  the TERM (terminate) signal) to the specified
               jobs or processes.  job may be a number, a string, `', `%', `+'
               or  `-'  as  described under Jobs.  Signals are either given by
               number or by name (as given in /usr/include/signal.h,  stripped
               of  the  prefix  `SIG').   There is no default job; saying just
               `kill' does not send a signal to the current job.  If the  sig-
               nal  being  sent  is TERM (terminate) or HUP (hangup), then the
               job or process is sent a CONT (continue) signal as  well.   The
               third form lists the signal names.

       limit [-h] [resource [maximum-use]]
               Limits  the consumption by the current process and each process
               it creates to not individually exceed maximum-use on the speci-
               fied  resource.   If  no maximum-use is given, then the current
               limit is printed; if no resource is given, then all limitations
               are  given.   If the -h flag is given, the hard limits are used
               instead of the current limits.  The hard limits impose a  ceil-
               ing  on  the values of the current limits.  Only the super-user

               filesize
                      the largest single file which can be created

               datasize
                      the  maximum growth of the data+stack region via sbrk(2)
                      beyond the end of the program text

               stacksize
                      the maximum size  of  the  automatically-extended  stack
                      region

               coredumpsize
                      the size of the largest core dump that will be created

               memoryuse
                      the maximum amount of physical memory a process may have
                      allocated to it at a given time

               descriptors or openfiles
                      the maximum number of open files for this process

               concurrency
                      the maximum number of threads for this process

               memorylocked
                      the maximum size which a process may  lock  into  memory
                      using mlock(2)

               maxproc
                      the  maximum  number  of simultaneous processes for this
                      user id

               sbsize the maximum size of socket buffer usage for this user

               maximum-use may be given as a (floating point or integer)  num-
               ber  followed  by  a  scale  factor.  For all limits other than
               cputime the default scale is `k' or `kilobytes' (1024 bytes); a
               scale  factor  of  `m'  or  `megabytes'  may also be used.  For
               cputime the default scaling is `seconds', while `m' for minutes
               or  `h' for hours, or a time of the form `mm:ss' giving minutes
               and seconds may be used.

               For both resource names and scale factors, unambiguous prefixes
               of the names suffice.

       log (+) Prints  the watch shell variable and reports on each user indi-
               cated in watch who is logged in, regardless of when  they  last
               logged in.  See also watchlog.

       login   Terminates  a  login  shell,  replacing  it with an instance of
               /bin/login. This is one way to log off, included  for  compati-
               bility with sh(1).

       logout  Terminates  a  login  shell.  Especially useful if ignoreeof is
               set.

               =   Socket (systems with sockets only)
               @   Symbolic link (systems with symbolic links only)
               +   Hidden  directory  (AIX  only)  or context dependent (HP/UX
                   only)
               :   Network special (HP/UX only)

               If the listlinks shell variable  is  set,  symbolic  links  are
               identified  in  more detail (on only systems that have them, of
               course):

               @   Symbolic link to a non-directory
               >   Symbolic link to a directory
               &   Symbolic link to nowhere

               listlinks also slows down ls-F and  causes  partitions  holding
               files pointed to by symbolic links to be mounted.

               If  the  listflags shell variable is set to `x', `a' or `A', or
               any combination thereof (e.g., `xA'), they are used as flags to
               ls-F, making it act like `ls -xF', `ls -Fa', `ls -FA' or a com-
               bination (e.g., `ls -FxA').  On machines where `ls -C'  is  not
               the default, ls-F acts like `ls -CF', unless listflags contains
               an `x', in which case it acts like `ls -xF'.  ls-F  passes  its
               arguments  to  ls(1)  if it is given any switches, so `alias ls
               ls-F' generally does the right thing.

               The ls-F builtin can list files using different colors  depend-
               ing  on the filetype or extension.  See the color tcsh variable
               and the LS_COLORS environment variable.

       migrate [-site] pid|%jobid ... (+)
       migrate -site (+)
               The first form migrates the process or job to the  site  speci-
               fied  or  the  default site determined by the system path.  The
               second form is equivalent to `migrate -site  $$':  it  migrates
               the current process to the specified site.  Migrating the shell
               itself can cause unexpected behavior, because  the  shell  does
               not like to lose its tty.  (TCF only)

       newgrp [-] group (+)
               Equivalent  to `exec newgrp'; see newgrp(1).  Available only if
               the shell was so compiled; see the version shell variable.

       nice [+number] [command]
               Sets the scheduling priority for the shell to number, or, with-
               out  number, to 4.  With command, runs command at the appropri-
               ate priority.  The greater the number, the less cpu the process
               gets.   The  super-user  may specify negative priority by using
               `nice -number ...'.  Command is always executed in a sub-shell,
               and the restrictions placed on commands in simple if statements
               apply.

       nohup [command]
               With command, runs command such that it will ignore hangup sig-
               nals.   Note  that  commands  may  set  their  own  response to
               hangups, overriding nohup.  Without  an  argument  (allowed  in
               only  a  shell  script), causes the shell to ignore hangups for

       onintr [-|label]
               Controls  the action of the shell on interrupts.  Without argu-
               ments, restores the default action of the shell on  interrupts,
               which  is to terminate shell scripts or to return to the termi-
               nal command input level.  With `-', causes all interrupts to be
               ignored.   With  label,  causes  the  shell  to execute a `goto
               label' when an interrupt is received or a child process  termi-
               nates because it was interrupted.

               onintr  is ignored if the shell is running detached and in sys-
               tem startup files (see FILES), where  interrupts  are  disabled
               anyway.

       popd [-p] [-l] [-n|-v] [+n]
               Without  arguments, pops the directory stack and returns to the
               new top directory.  With a number `+n', discards the n'th entry
               in the stack.

               Finally,  all  forms  of  popd print the final directory stack,
               just like dirs.  The pushdsilent shell variable can be  set  to
               prevent  this and the -p flag can be given to override pushdsi-
               lent.  The -l, -n and -v flags have the same effect on popd  as
               on dirs.  (+)

       printenv [name] (+)
               Prints  the  names  and values of all environment variables or,
               with name, the value of the environment variable name.

       pushd [-p] [-l] [-n|-v] [name|+n]
               Without arguments, exchanges the top two elements of the direc-
               tory  stack.   If  pushdtohome  is set, pushd without arguments
               does `pushd ~', like cd.  (+) With  name,  pushes  the  current
               working directory onto the directory stack and changes to name.
               If name is `-' it is interpreted as the previous working direc-
               tory (see Filename substitution).  (+) If dunique is set, pushd
               removes any instances of name from the stack before pushing  it
               onto  the  stack.  (+) With a number `+n', rotates the nth ele-
               ment of the directory stack around to be the  top  element  and
               changes  to  it.   If  dextract  is  set,  however,  `pushd +n'
               extracts the nth directory, pushes it onto the top of the stack
               and changes to it.  (+)

               Finally,  all  forms  of pushd print the final directory stack,
               just like dirs.  The pushdsilent shell variable can be  set  to
               prevent  this and the -p flag can be given to override pushdsi-
               lent.  The -l, -n and -v flags have the same effect on pushd as
               on dirs.  (+)

       rehash  Causes  the internal hash table of the contents of the directo-
               ries in the path variable to be recomputed.  This is needed  if
               new  commands  are  added  to directories in path while you are
               logged in.  This should be necessary only if you  add  commands
               to  one  of  your  own  directories, or if a systems programmer
               changes the contents of one of the  system  directories.   Also
               flushes the cache of home directories built by tilde expansion.


       sched (+)
       sched [+]hh:mm command (+)
       sched -n (+)
               The first form prints  the  scheduled-event  list.   The  sched
               shell  variable  may  be  set to define the format in which the
               scheduled-event list is printed.  The second form adds  command
               to the scheduled-event list.  For example,

                   > sched 11:00 echo It\'s eleven o\'clock.

               causes  the shell to echo `It's eleven o'clock.' at 11 AM.  The
               time may be in 12-hour AM/PM format

                   > sched 5pm set prompt='[%h] It\'s after 5; go home: >'

               or may be relative to the current time:

                   > sched +2:15 /usr/lib/uucp/uucico -r1 -sother

               A relative time specification may not use  AM/PM  format.   The
               third form removes item n from the event list:

                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother
                        2   Wed Apr  4 17:00  set prompt=[%h] It's after 5; go
                   home: >
                   > sched -2
                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother

               A command in the scheduled-event list is executed  just  before
               the  first prompt is printed after the time when the command is
               scheduled.  It is possible to miss the exact time when the com-
               mand  is  to be run, but an overdue command will execute at the
               next prompt.  A command which comes  due  while  the  shell  is
               waiting  for user input is executed immediately.  However, nor-
               mal operation of an already-running command will not be  inter-
               rupted so that a scheduled-event list element may be run.

               This  mechanism  is  similar to, but not the same as, the at(1)
               command on some Unix systems.  Its major disadvantage  is  that
               it  may  not  run a command at exactly the specified time.  Its
               major advantage is that because sched runs  directly  from  the
               shell,  it  has access to shell variables and other structures.
               This provides a mechanism for changing one's  working  environ-
               ment based on the time of day.

       set
       set name ...
       set name=word ...
       set [-r] [-f|-l] name=(wordlist) ... (+)
       set name[index]=word ...
       set -r (+)
       set -r name ... (+)
       set -r name=word ... (+)
               The  first  form  of  the command prints the value of all shell
               word;  this component must already exist.  The sixth form lists
               only the names of all shell variables that are read-only.   The
               seventh  form  makes  name  read-only,  whether or not it has a
               value.  The second form sets name  to  the  null  string.   The
               eighth  form is the same as the third form, but make name read-
               only at the same time.

               These arguments can be repeated to set  and/or  make  read-only
               multiple  variables  in  a  single set command.  Note, however,
               that variable expansion happens for all  arguments  before  any
               setting  occurs.   Note  also  that `=' can be adjacent to both
               name and word or separated from both by whitespace, but  cannot
               be  adjacent  to  only  one  or  the other.  See also the unset
               builtin command.

       setenv [name [value]]
               Without arguments, prints the names and values of all  environ-
               ment variables.  Given name, sets the environment variable name
               to value or, without value, to the null string.

       setpath path (+)
               Equivalent to setpath(1).  (Mach only)

       setspath LOCAL|site|cpu ... (+)
               Sets the system execution path.  (TCF only)

       settc cap value (+)
               Tells the shell to believe that the terminal capability cap (as
               defined in termcap(5)) has the value value.  No sanity checking
               is done.  Concept terminal users may have to `settc xn  no'  to
               get proper wrapping at the rightmost column.

       setty [-d|-q|-x] [-a] [[+|-]mode] (+)
               Controls  which  tty  modes (see Terminal management) the shell
               does not allow to change.  -d, -q or -x tells setty to  act  on
               the `edit', `quote' or `execute' set of tty modes respectively;
               without -d, -q or -x, `execute' is used.

               Without other arguments, setty lists the modes  in  the  chosen
               set  which are fixed on (`+mode') or off (`-mode').  The avail-
               able modes, and thus the display, vary from system  to  system.
               With  -a,  lists all tty modes in the chosen set whether or not
               they are fixed.  With +mode, -mode or mode, fixes  mode  on  or
               off  or removes control from mode in the chosen set.  For exam-
               ple, `setty +echok echoe' fixes `echok' mode on and allows com-
               mands  to  turn  `echoe' mode on or off, both when the shell is
               executing commands.

       setxvers [string] (+)
               Set the experimental version prefix to string, or removes it if
               string is omitted.  (TCF only)

       shift [variable]
               Without  arguments,  discards argv[1] and shifts the members of
               argv to the left.  It is an error for argv not to be set or  to
               have  less than one word as value.  With variable, performs the
               same function on variable.

       stop %job|pid ...
               Stops  the  specified  jobs or processes which are executing in
               the background.  job may be a number, a string, `', `%', `+' or
               `-'  as  described under Jobs.  There is no default job; saying
               just `stop' does not stop the current job.

       suspend Causes the shell to stop in its tracks, much as if it had  been
               sent  a  stop  signal with ^Z.  This is most often used to stop
               shells started by su(1).

       switch (string)
       case str1:
           ...
           breaksw
       ...
       default:
           ...
           breaksw
       endsw   Each case label is successively matched, against the  specified
               string  which is first command and filename expanded.  The file
               metacharacters `*', `?' and `[...]'  may be used  in  the  case
               labels,  which  are  variable  expanded.  If none of the labels
               match before a `default' label is  found,  then  the  execution
               begins  after  the  default  label.   Each  case  label and the
               default label must appear at the beginning of a line.  The com-
               mand  breaksw  causes  execution  to  continue after the endsw.
               Otherwise control may fall  through  case  labels  and  default
               labels  as  in C.  If no label matches and there is no default,
               execution continues after the endsw.

       telltc (+)
               Lists the values of all terminal capabilities (see termcap(5)).

       time [command]
               Executes command (which must be a simple command, not an alias,
               a pipeline, a command list or a parenthesized command list) and
               prints a time summary as described under the time variable.  If
               necessary, an extra shell is created to print the time  statis-
               tic when the command completes.  Without command, prints a time
               summary for the current shell and its children.

       umask [value]
               Sets the file creation mask to value, which is given in  octal.
               Common  values  for  the mask are 002, giving all access to the
               group and read and execute access to others,  and  022,  giving
               read  and  execute  access  to  the  group and others.  Without
               value, prints the current file creation mask.

       unalias pattern
               Removes all aliases whose names  match  pattern.   `unalias  *'
               thus removes all aliases.  It is not an error for nothing to be
               unaliased.

       uncomplete pattern (+)
               Removes all completions whose names match pattern.  `uncomplete
               *'  thus removes all completions.  It is not an error for noth-
               Removes the limitation on resource or, if no resource is speci-
               fied, all resource limitations.   With  -h,  the  corresponding
               hard limits are removed.  Only the super-user may do this.

       unset pattern
               Removes  all  variables  whose names match pattern, unless they
               are read-only.  `unset *' thus  removes  all  variables  unless
               they are read-only; this is a bad idea.  It is not an error for
               nothing to be unset.

       unsetenv pattern
               Removes all environment variables whose  names  match  pattern.
               `unsetenv  *' thus removes all environment variables; this is a
               bad idea.  It is not an error for nothing to be unsetenved.

       ver [systype [command]] (+)
               Without arguments, prints SYSTYPE.  With systype, sets  SYSTYPE
               to  systype.   With systype and command, executes command under
               systype.  systype may  be  `bsd4.3'  or  `sys5.3'.   (Domain/OS
               only)

       wait    The  shell  waits  for  all  background  jobs.  If the shell is
               interactive, an interrupt will disrupt the wait and  cause  the
               shell  to  print  the  names and job numbers of all outstanding
               jobs.

       warp universe (+)
               Sets the universe to universe.  (Convex/OS only)

       watchlog (+)
               An alternate name for the log builtin command  (q.v.).   Avail-
               able  only  if the shell was so compiled; see the version shell
               variable.

       where command (+)
               Reports all known  instances  of  command,  including  aliases,
               builtins and executables in path.

       which command (+)
               Displays  the  command that will be executed by the shell after
               substitutions, path searching, etc.   The  builtin  command  is
               just  like  which(1), but it correctly reports tcsh aliases and
               builtins and is 10 to 100 times faster.  See  also  the  which-
               command editor command.

       while (expr)
       ...
       end     Executes  the  commands  between the while and the matching end
               while expr (an  expression,  as  described  under  Expressions)
               evaluates  non-zero.   while and end must appear alone on their
               input lines.  break and continue may be used  to  terminate  or
               continue the loop prematurely.  If the input is a terminal, the
               user is prompted the first time through the loop as with  fore-
               ach.

   Special aliases (+)
       If  set,  each of these aliases executes automatically at the indicated
                   > alias cwdcmd  'echo -n "^[]2;${HOST}:$cwd ^G"'

               then the shell will change the title of the running xterm(1) to
               be the name of the host, a colon, and the full current  working
               directory.  A fancier way to do that is

                   >          alias          cwdcmd          'echo          -n
                   "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'

               This will put the hostname and working directory on  the  title
               bar but only the hostname in the icon manager menu.

               Note  that  putting  a cd, pushd or popd in cwdcmd may cause an
               infinite loop.  It is the author's opinion that anyone doing so
               will get what they deserve.

       jobcmd  Runs  before  each  command  gets executed, or when the command
               changes state.  This is similar to postcmd,  but  it  does  not
               print builtins.

                   > alias jobcmd  'echo -n "^[]2\;\!#^G"'

               then  executing  vi  foo.c  will  put the command string in the
               xterm title bar.

       helpcommand
               Invoked by the run-help editor command.  The command  name  for
               which  help is sought is passed as sole argument.  For example,
               if one does

                   > alias helpcommand '\!:1 --help'

               then the help display of the command itself  will  be  invoked,
               using  the  GNU help calling convention.  Currently there is no
               easy way to account for various calling conventions (e.g.,  the
               customary Unix `-h'), except by using a table of many commands.

       periodic
               Runs every tperiod minutes.  This provides a  convenient  means
               for checking on common but infrequent changes such as new mail.
               For example, if one does

                   > set tperiod = 30
                   > alias periodic checknews

               then the checknews(1) program runs every 30 minutes.  If  peri-
               odic  is set but tperiod is unset or set to 0, periodic behaves
               like precmd.

       precmd  Runs just before each prompt is printed.  For example,  if  one
               does

                   > alias precmd date

               then  date(1)  runs just before the shell prompts for each com-
               mand.  There are no limits on what precmd can be set to do, but
               discretion should be used.
               themselves  specify an interpreter.  The first word should be a
               full path name to the desired interpreter (e.g., `/bin/csh'  or
               `/usr/local/bin/tcsh').

   Special shell variables
       The  variables  described  in  this section have special meaning to the
       shell.

       The shell sets addsuffix, argv, autologout, command, echo_style,  edit,
       gid,  group, home, loginsh, oid, path, prompt, prompt2, prompt3, shell,
       shlvl, tcsh, term, tty, uid, user and version at startup; they  do  not
       change  thereafter  unless changed by the user.  The shell updates cwd,
       dirstack, owd and status when necessary, and sets logout on logout.

       The shell synchronizes afsuser, group, home, path, shlvl, term and user
       with the environment variables of the same names: whenever the environ-
       ment variable changes the shell changes the corresponding  shell  vari-
       able  to match (unless the shell variable is read-only) and vice versa.
       Note that although cwd and PWD have identical meanings,  they  are  not
       synchronized in this manner, and that the shell automatically intercon-
       verts the different formats of path and PATH.

       addsuffix (+)
               If set, filename completion adds `/' to the end of  directories
               and  a  space  to the end of normal files when they are matched
               exactly.  Set by default.

       afsuser (+)
               If set, autologout's autolock feature uses its value instead of
               the local username for kerberos authentication.

       ampm (+)
               If set, all times are shown in 12-hour AM/PM format.

       argv    The  arguments  to  the shell.  Positional parameters are taken
               from argv, i.e., `$1' is replaced by `$argv[1]', etc.   Set  by
               default, but usually empty in interactive shells.

       autocorrect (+)
               If  set, the spell-word editor command is invoked automatically
               before each completion attempt.

       autoexpand (+)
               If set, the expand-history editor command is invoked  automati-
               cally before each completion attempt.

       autolist (+)
               If set, possibilities are listed after an ambiguous completion.
               If set to `ambiguous', possibilities are listed  only  when  no
               new characters are added by completion.

       autologout (+)
               The  first  word  is the number of minutes of inactivity before
               automatic logout.  The optional second word is  the  number  of
               minutes of inactivity before automatic locking.  When the shell
               automatically logs out, it prints `auto-logout', sets the vari-
               able logout to `automatic' and exits.  When the shell automati-

       backslash_quote (+)
               If set, backslashes (`\') always quote `\', `'', and `"'.  This
               may make complex quoting tasks easier, but it can cause  syntax
               errors in csh(1) scripts.

       catalog The  file  name  of  the  message  catalog.   If  set, tcsh use
               `tcsh.${catalog}' as  a  message  catalog  instead  of  default
               `tcsh'.

       cdpath  A list of directories in which cd should search for subdirecto-
               ries if they aren't found in the current directory.

       color   If set, it enables color display for the builtin  ls-F  and  it
               passes  --color=auto  to  ls.   Alternatively, it can be set to
               only ls-F or only ls to enable color to only one command.  Set-
               ting it to nothing is equivalent to setting it to (ls-F ls).

       colorcat
               If set, it enables color escape sequence for NLS message files.
               And display colorful NLS messages.

       command (+)
               If set, the command which was passed to the shell with  the  -c
               flag (q.v.).

       complete (+)
               If  set to `enhance', completion 1) ignores case and 2) consid-
               ers periods, hyphens and underscores (`.', `-' and `_')  to  be
               word separators and hyphens and underscores to be equivalent.

       continue (+)
               If  set  to  a  list  of  commands, the shell will continue the
               listed commands, instead of starting a new one.

       continue_args (+)
               Same as continue, but the shell will execute:

                   echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>

       correct (+)
               If set to `cmd', commands are automatically spelling-corrected.
               If set to `complete', commands are automatically completed.  If
               set to `all', the entire command line is corrected.

       cwd     The full pathname of  the  current  directory.   See  also  the
               dirstack and owd shell variables.

       dextract (+)
               If  set,  `pushd +n' extracts the nth directory from the direc-
               tory stack rather than rotating it to the top.

       dirsfile (+)
               The default location in which `dirs -S' and `dirs -L' look  for
               a  history  file.   If unset, ~/.cshdirs is used.  Because only
               ~/.tcshrc  is  normally  sourced  before  ~/.cshdirs,  dirsfile
               should be set in ~/.tcshrc rather than ~/.login.


       dspmbyte (+)
               If  set  to  `euc',  it  enables  display  and   editing   EUC-
               kanji(Japanese) code.  If set to `sjis', it enables display and
               editing Shift-JIS(Japanese) code.  If set to `big5', it enables
               display  and  editing Big5(Chinese) code.  If set to `utf8', it
               enables display and editing Utf8(Unicode) code.  If set to  the
               following  format,  it  enables display and editing of original
               multi-byte code format:

                   > set dspmbyte = 0000....(256 bytes)....0000

               The table requires just 256 bytes.  Each character of 256 char-
               acters  corresponds  (from  left  to  right) to the ASCII codes
               0x00, 0x01, ... 0xff.  Each character is set  to  number  0,1,2
               and 3.  Each number has the following meaning:
                 0 ... not used for multi-byte characters.
                 1 ... used for the first byte of a multi-byte character.
                 2 ... used for the second byte of a multi-byte character.
                 3  ...  used  for  both  the  first byte and second byte of a
               multi-byte character.

                 Example:
               If set to `001322', the first  character  (means  0x00  of  the
               ASCII code) and second character (means 0x01 of ASCII code) are
               set to `0'.  Then, it is not used  for  multi-byte  characters.
               The  3rd  character (0x02) is set to '2', indicating that it is
               used for the first byte of a  multi-byte  character.   The  4th
               character(0x03) is set '3'.  It is used for both the first byte
               and the second byte of a multi-byte character.  The 5th and 6th
               characters (0x04,0x05) are set to '2', indicating that they are
               used for the second byte of a multi-byte character.

               The GNU fileutils version of ls cannot display multi-byte file-
               names  without  the -N ( --literal ) option.   If you are using
               this version, set the second word of dspmbyte to "ls".  If not,
               for example, "ls-F -l" cannot display multi-byte filenames.

                 Note:
               This  variable  can only be used if KANJI and DSPMBYTE has been
               defined at compile time.

       dunique (+)
               If set, pushd removes any instances  of  name  from  the  stack
               before pushing it onto the stack.

       echo    If  set,  each command with its arguments is echoed just before
               it is executed.  For non-builtin commands all expansions  occur
               before echoing.  Builtin commands are echoed before command and
               filename substitution, because  these  substitutions  are  then
               done selectively.  Set by the -x command line option.

               Set by default to the local system default.  The BSD and System
               V options are described in the echo(1) man pages on the  appro-
               priate systems.

       edit (+)
               If  set,  the  command-line  editor is used.  Set by default in
               interactive shells.

       ellipsis (+)
               If set, the `%c'/`%.' and `%C' prompt sequences (see the prompt
               shell  variable)  indicate skipped directories with an ellipsis
               (`...')  instead of `/<skipped>'.

       fignore (+)
               Lists file name suffixes to be ignored by completion.

       filec   In tcsh, completion is always used and this variable is ignored
               by  default. If edit is unset, then the traditional csh comple-
               tion is used.  If set in csh, filename completion is used.

       gid (+) The user's real group ID.

       group (+)
               The user's group name.

       histchars
               A string value determining the characters used in History  sub-
               stitution  (q.v.).  The first character of its value is used as
               the history substitution character, replacing the default char-
               acter  `!'.   The  second  character  of its value replaces the
               character `^' in quick substitutions.

       histdup (+)
               Controls handling of duplicate entries in the history list.  If
               set to `all' only unique history events are entered in the his-
               tory list.  If set to `prev' and the last history event is  the
               same  as  the  current command, then the current command is not
               entered in the history.  If set to `erase' and the  same  event
               is  found  in  the history list, that old event gets erased and
               the current one gets inserted.  Note that the `prev' and  `all'
               options renumber history events so there are no gaps.

       histfile (+)
               The  default  location  in  which `history -S' and `history -L'
               look for a history file.  If unset, ~/.history is used.   hist-
               file  is  useful  when  sharing the same home directory between
               different machines, or when saving separate histories  on  dif-
               ferent  terminals.   Because only ~/.tcshrc is normally sourced
               before ~/.history, histfile should be set in  ~/.tcshrc  rather
               than ~/.login.

       histlit (+)
               If  set, builtin and editor commands and the savehist mechanism
               use the literal (unexpanded) form of lines in the history list.
               See also the toggle-literal-history editor command.

       ignoreeof
               If set to the empty string or `0' and the  input  device  is  a
               terminal,  the  end-of-file  command  (usually generated by the
               user by typing `^D' on an empty line) causes the shell to print
               `Use  "exit" to leave tcsh.' instead of exiting.  This prevents
               the shell from accidentally being killed.  If set to  a  number
               n,  the  shell ignores n - 1 consecutive end-of-files and exits
               on the nth.  (+) If unset, `1' is used, i.e., the  shell  exits
               on a single `^D'.

       implicitcd (+)
               If set, the shell treats a directory name typed as a command as
               though it were a request to change to that directory.   If  set
               to  verbose,  the change of directory is echoed to the standard
               output.  This behavior is inhibited  in  non-interactive  shell
               scripts,  or  for  command  strings  with  more  than one word.
               Changing directory takes precedence over executing a like-named
               command,  but  it is done after alias substitutions.  Tilde and
               variable expansions work as expected.

       inputmode (+)
               If set to `insert' or `overwrite', puts the  editor  into  that
               input mode at the beginning of each line.

       killdup (+)
               Controls  handling  of  duplicate entries in the kill ring.  If
               set to `all' only unique strings are entered in the kill  ring.
               If  set to `prev' and the last killed string is the same as the
               current killed string, then the current string is  not  entered
               in the ring.  If set to `erase' and the same string is found in
               the kill ring, the old string is erased and the current one  is
               inserted.

       killring (+)
               Indicates  the number of killed strings to keep in memory.  Set
               to `30' by default.  If unset or set  to  less  than  `2',  the
               shell will only keep the most recently killed string.

       listflags (+)
               If  set  to  `x', `a' or `A', or any combination thereof (e.g.,
               `xA'), they are used as flags to ls-F, making it act  like  `ls
               -xF',  `ls  -Fa',  `ls -FA' or a combination (e.g., `ls -FxA'):
               `a' shows all files (even if they start with a `.'), `A'  shows
               all  files  but  `.'  and `..', and `x' sorts across instead of
               down.  If the second word of listflags is set, it  is  used  as
               the path to `ls(1)'.

       listjobs (+)
               If set, all jobs are listed when a job is suspended.  If set to
               `long', the listing is in long format.

       listlinks (+)
               If set, the ls-F builtin command shows  the  type  of  file  to
               which each symbolic link points.

       listmax (+)
               The  maximum number of items which the list-choices editor com-

       logout (+)
               Set by the shell to `normal' before  a  normal  logout,  `auto-
               matic'  before  an  automatic logout, and `hangup' if the shell
               was killed by a hangup signal (see Signal handling).  See  also
               the autologout shell variable.

       mail    The  names  of  the  files or directories to check for incoming
               mail, separated by whitespace, and  optionally  preceded  by  a
               numeric  word.   Before  each prompt, if 10 minutes have passed
               since the last check, the shell checks each file and says  `You
               have new mail.' (or, if mail contains multiple files, `You have
               new mail in name.') if the filesize is  greater  than  zero  in
               size  and has a modification time greater than its access time.

               If you are in a login shell, then  no  mail  file  is  reported
               unless  it  has  been  modified  after  the  time the shell has
               started up, to prevent  redundant  notifications.   Most  login
               programs  will  tell  you whether or not you have mail when you
               log in.

               If a file specified in mail is  a  directory,  the  shell  will
               count  each  file  within that directory as a separate message,
               and will report `You have n mails.' or `You  have  n  mails  in
               name.'  as appropriate.  This functionality is provided primar-
               ily for those systems which store mail in this manner, such  as
               the Andrew Mail System.

               If the first word of mail is numeric it is taken as a different
               mail checking interval, in seconds.

               Under very rare circumstances, the shell may report  `You  have
               mail.' instead of `You have new mail.'

       matchbeep (+)
               If   set  to  `never',  completion  never  beeps.   If  set  to
               `nomatch', it beeps only when there is no  match.   If  set  to
               `ambiguous,  it  beeps when there are multiple matches.  If set
               to `notunique', it beeps when there  is  one  exact  and  other
               longer matches.  If unset, `ambiguous' is used.

       nobeep (+)
               If  set, beeping is completely disabled.  See also visiblebell.

       noclobber
               If set, restrictions are placed on output redirection to insure
               that  files  are not accidentally destroyed and that `>>' redi-
               rections  refer  to  existing  files,  as  described   in   the
               Input/output section.

       noding  If  set,  disable  the  printing  of `DING!' in the prompt time
               specifiers at the change of hour.

       noglob  If set, Filename substitution and Directory stack  substitution
               (q.v.)  are  inhibited.   This  is most useful in shell scripts
               which do not deal with filenames, or after a list of  filenames
               untouched rather than causing an error.  It is still  an  error
               for  the  substitution  to  be  malformed, e.g., `echo [' still
               gives an error.

       nostat (+)
               A list of directories (or glob-patterns  which  match  directo-
               ries;  see  Filename substitution) that should not be stat(2)ed
               during a completion operation.  This is usually used to exclude
               directories  which  take  too much time to stat(2), for example
               /afs.

       notify  If set, the shell  announces  job  completions  asynchronously.
               The  default is to present job completions just before printing
               a prompt.

       oid (+) The user's real organization ID.  (Domain/OS only)

       owd (+) The old working directory, equivalent to the `-' used by cd and
               pushd.  See also the cwd and dirstack shell variables.

       path    A list of directories in which to look for executable commands.
               A null word specifies the current directory.  If  there  is  no
               path  variable then only full path names will execute.  path is
               set by the shell at startup from the PATH environment  variable
               or, if PATH does not exist, to a system-dependent default some-
               thing like `(/usr/local/bin /usr/bsd /bin  /usr/bin  .)'.   The
               shell  may  put  `.'  first or last in path or omit it entirely
               depending on how it was compiled; see the version  shell  vari-
               able.   A shell which is given neither the -c nor the -t option
               hashes the contents of the directories in  path  after  reading
               ~/.tcshrc  and each time path is reset.  If one adds a new com-
               mand to a directory in path while the shell is active, one  may
               need to do a rehash for the shell to find it.

       printexitvalue (+)
               If set and an interactive program exits with a non-zero status,
               the shell prints `Exit status'.

       prompt  The string which is printed before reading  each  command  from
               the   terminal.   prompt  may  include  any  of  the  following
               formatting sequences (+),  which  are  replaced  by  the  given
               information:

               %/  The current working directory.
               %~  The  current  working directory, but with one's home direc-
                   tory represented by `~' and other users'  home  directories
                   represented   by  `~user'  as  per  Filename  substitution.
                   `~user' substitution happens only if the shell has  already
                   used `~user' in a pathname in the current session.
               %c[[0]n], %.[[0]n]
                   The trailing component of the current working directory, or
                   n trailing components if a digit n is given.  If  n  begins
                   with  `0',  the  number  of  skipped components precede the
                   trailing component(s) in the  format  `/<skipped>trailing'.
                   If  the  ellipsis shell variable is set, skipped components
                   are  represented  by  an  ellipsis  so  the  whole  becomes
                   `...trailing'.   `~' substitution is done as in `%~' above,

               %B (%b)
                   Start (stop) boldfacing mode.
               %U (%u)
                   Start (stop) underline mode.
               %t, %@
                   The time of day in 12-hour AM/PM format.
               %T  Like  `%t',  but  in 24-hour format (but see the ampm shell
                   variable).
               %p  The `precise' time of day in  12-hour  AM/PM  format,  with
                   seconds.
               %P  Like  `%p',  but  in 24-hour format (but see the ampm shell
                   variable).
               \c  c is parsed as in bindkey.
               ^c  c is parsed as in bindkey.
               %%  A single `%'.
               %n  The user name.
               %j  The number of jobs.
               %d  The weekday in `Day' format.
               %D  The day in `dd' format.
               %w  The month in `Mon' format.
               %W  The month in `mm' format.
               %y  The year in `yy' format.
               %Y  The year in `yyyy' format.
               %l  The shell's tty.
               %L  Clears from the end of the prompt to end of the display  or
                   the end of the line.
               %$  Expands  the shell or environment variable name immediately
                   after the `$'.
               %#  `>' (or the first character of the promptchars shell  vari-
                   able)  for  normal  users,  `#' (or the second character of
                   promptchars) for the superuser.
               %{string%}
                   Includes string as a literal escape sequence.  It should be
                   used only to change terminal attributes and should not move
                   the cursor location.  This cannot be the last  sequence  in
                   prompt.
               %?  The  return  code  of  the command executed just before the
                   prompt.
               %R  In prompt2, the status of the parser.  In prompt3, the cor-
                   rected string.  In history, the history string.

               `%B',  `%S', `%U' and `%{string%}' are available in only eight-
               bit-clean shells; see the version shell variable.

               The bold, standout and underline sequences are  often  used  to
               distinguish a superuser shell.  For example,

                   > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
                   tut [37] [2:54pm] [/usr/accts/sys] you rang? _

               If  `%t',  `%@', `%T', `%p', or `%P' is used, and noding is not
               set, then print `DING!' on the change of hour (i.e, `:00'  min-
               utes) instead of the actual time.

               Set by default to `%# ' in interactive shells.

       prompt2 (+)
               default to `CORRECT>%R (y|n|e|a)? ' in interactive shells.

       promptchars (+)
               If  set  (to  a  two-character  string),  the  `%#'  formatting
               sequence in the prompt shell  variable  is  replaced  with  the
               first  character  for normal users and the second character for
               the superuser.

       pushdtohome (+)
               If set, pushd without arguments does `pushd ~', like cd.

       pushdsilent (+)
               If set, pushd and popd do not print the directory stack.

       recexact (+)
               If set, completion completes on an exact match even if a longer
               match is possible.

       recognize_only_executables (+)
               If  set,  command  listing displays only files in the path that
               are executable.  Slow.

       rmstar (+)
               If set, the user is prompted before `rm *' is executed.

       rprompt (+)
               The string to print on the right-hand side of the screen (after
               the  command  input)  when the prompt is being displayed on the
               left.  It recognizes the same formatting characters as  prompt.
               It  will  automatically disappear and reappear as necessary, to
               ensure that command input isn't obscured, and will appear  only
               if  the  prompt, command input, and itself will fit together on
               the first line.  If  edit  isn't  set,  then  rprompt  will  be
               printed after the prompt and before the command input.

       savedirs (+)
               If  set, the shell does `dirs -S' before exiting.  If the first
               word is set to a number, at  most  that  many  directory  stack
               entries are saved.

       savehist
               If  set,  the  shell  does `history -S' before exiting.  If the
               first word is set to a number, at  most  that  many  lines  are
               saved.  (The number must be less than or equal to history.)  If
               the second word is set to `merge', the history list  is  merged
               with  the  existing  history  file  instead of replacing it (if
               there is one) and sorted by time  stamp  and  the  most  recent
               events are retained.  (+)

       sched (+)
               The  format in which the sched builtin command prints scheduled
               events; if not  given,  `%h\t%T\t%R\n'  is  used.   The  format
               sequences  are  described above under prompt; note the variable
               meaning of `%R'.

       shell   The file in which the shell resides.  This is used  in  forking
               shells  to  interpret  files  which  have execute bits set, but
               abnormally, then 0200 is added to the status.  Builtin commands
               which  fail  return exit status `1', all other builtin commands
               return status `0'.

       symlinks (+)
               Can be set to several different values to control symbolic link
               (`symlink') resolution:

               If  set to `chase', whenever the current directory changes to a
               directory containing a symbolic link, it  is  expanded  to  the
               real name of the directory to which the link points.  This does
               not work for the user's home directory; this is a bug.

               If set to `ignore', the shell  tries  to  construct  a  current
               directory relative to the current directory before the link was
               crossed.  This means that cding through  a  symbolic  link  and
               then  `cd  ..'ing  returns one to the original directory.  This
               affects only builtin commands and filename completion.

               If set to `expand', the shell tries to fix  symbolic  links  by
               actually  expanding arguments which look like path names.  This
               affects any command, not just  builtins.   Unfortunately,  this
               does  not  work  for hard-to-recognize filenames, such as those
               embedded in command options.  Expansion  may  be  prevented  by
               quoting.  While this setting is usually the most convenient, it
               is sometimes misleading and sometimes confusing when  it  fails
               to  recognize  an argument which should be expanded.  A compro-
               mise is to use `ignore' and use the editor  command  normalize-
               path (bound by default to ^X-n) when necessary.

               Some  examples  are  in  order.   First, let's set up some play
               directories:

                   > cd /tmp
                   > mkdir from from/src to
                   > ln -s from/src to/dst

               Here's the behavior with symlinks unset,

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/from

               here's the behavior with symlinks set to `chase',

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/from/src
                   > cd ..; echo $cwd
                   /tmp/from

               here's the behavior with symlinks set to `ignore',

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/to
                   > cd ".."; echo $cwd
                   /tmp/from
                   > /bin/echo ..
                   /tmp/to
                   > /bin/echo ".."
                   ..

               Note that `expand' expansion 1) works just  like  `ignore'  for
               builtins  like  cd,  2) is prevented by quoting, and 3) happens
               before filenames are passed to non-builtin commands.

       tcsh (+)
               The version number of the shell in the format `R.VV.PP',  where
               `R'  is  the major release number, `VV' the current version and
               `PP' the patchlevel.

       term    The terminal type.  Usually set in ~/.login as described  under
               Startup and shutdown.

       time    If set to a number, then the time builtin (q.v.) executes auto-
               matically after each command which takes more  than  that  many
               CPU seconds.  If there is a second word, it is used as a format
               string for the output of the time builtin.  (u)  The  following
               sequences may be used in the format string:

               %U  The time the process spent in user mode in cpu seconds.
               %S  The time the process spent in kernel mode in cpu seconds.
               %E  The elapsed (wall clock) time in seconds.
               %P  The CPU percentage computed as (%U + %S) / %E.
               %W  Number of times the process was swapped.
               %X  The average amount in (shared) text space used in Kbytes.
               %D  The  average  amount in (unshared) data/stack space used in
                   Kbytes.
               %K  The total space used (%X + %D) in Kbytes.
               %M  The maximum memory the process had in use at  any  time  in
                   Kbytes.
               %F  The  number of major page faults (page needed to be brought
                   from disk).
               %R  The number of minor page faults.
               %I  The number of input operations.
               %O  The number of output operations.
               %r  The number of socket messages received.
               %s  The number of socket messages sent.
               %k  The number of signals received.
               %w  The number of voluntary context switches (waits).
               %c  The number of involuntary context switches.

               Only the first four sequences are supported on systems  without
               BSD  resource limit functions.  The default time format is `%Uu
               %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww'  for  systems  that  support
               resource  usage  reporting and `%Uu %Ss %E %P' for systems that
               do not.

               Under Sequent's DYNIX/ptx, %X, %D, %K, %r and %s are not avail-
               able, but the following additional sequences are:

               %Y  The number of system calls performed.

               and  the  default  time  format  is  `%Uu  %Ss  $E  %P  %I+%Oio
               %Fpf+%Ww'.  Note that the CPU percentage  can  be  higher  than
               100% on multi-processors.

       tperiod (+)
               The period, in minutes, between executions of the periodic spe-
               cial alias.

       tty (+) The name of the tty, or empty if not attached to one.

       uid (+) The user's real user ID.

       user    The user's login name.

       verbose If set, causes the words of each command to be  printed,  after
               history  substitution  (if  any).   Set  by the -v command line
               option.

       version (+)
               The version ID stamp.  It contains the shell's  version  number
               (see  tcsh), origin, release date, vendor, operating system and
               machine (see VENDOR, OSTYPE and MACHTYPE) and a comma-separated
               list  of options which were set at compile time.  Options which
               are set by default in the distribution are noted.

               8b  The shell is eight bit clean; default
               7b  The shell is not eight bit clean
               nls The system's NLS is used; default for systems with NLS
               lf  Login shells execute /etc/csh.login before instead of after
                   /etc/csh.cshrc   and   ~/.login  before  instead  of  after
                   ~/.tcshrc and ~/.history.
               dl  `.' is put last in path for security; default
               nd  `.' is omitted from path for security
               vi  vi-style editing is the default rather than emacs
               dtr Login shells drop DTR when exiting
               bye bye is a synonym for logout and log is  an  alternate  name
                   for watchlog
               al  autologout is enabled; default
               kan Kanji  is used if appropriate according to locale settings,
                   unless the nokanji shell variable is set
               sm  The system's malloc(3) is used
               hb  The `#!<program> <args>' convention is emulated  when  exe-
                   cuting shell scripts
               ng  The newgrp builtin is available
               rh  The  shell attempts to set the REMOTEHOST environment vari-
                   able
               afs The shell verifies your password with the  kerberos  server
                   if  local authentication fails.  The afsuser shell variable
                   or the AFSUSER environment  variable  override  your  local
                   username if set.

               An  administrator may enter additional strings to indicate dif-
               ferences in the local version.

       visiblebell (+)
               If set, a screen flash is used rather than  the  audible  bell.

               reports activity of the user `george' on ttyd1, any user on the
               console, and oneself (or a trespasser) on any terminal.

               Logins and logouts are checked every 10 minutes by default, but
               the first word of watch can be set to a number to  check  every
               so many minutes.  For example,

                   set watch = (1 any any)

               reports any login/logout once every minute.  For the impatient,
               the log builtin command triggers a watch report  at  any  time.
               All  current logins are reported (as with the log builtin) when
               watch is first set.

               The who shell variable controls the format of watch reports.

       who (+) The format string for watch messages.  The following  sequences
               are replaced by the given information:

               %n  The name of the user who logged in/out.
               %a  The  observed  action,  i.e.,  `logged on', `logged off' or
                   `replaced olduser on'.
               %l  The terminal (tty) on which the user logged in/out.
               %M  The full hostname of the remote host,  or  `local'  if  the
                   login/logout was from the local host.
               %m  The  hostname  of the remote host up to the first `.'.  The
                   full name is printed if it is an IP address or an X  Window
                   System display.

               %M  and  %m are available on only systems that store the remote
               hostname in /etc/utmp.  If unset, `%n has %a %l  from  %m.'  is
               used,  or  `%n  has  %a  %l.'  on systems which don't store the
               remote hostname.

       wordchars (+)
               A list of non-alphanumeric characters to be considered part  of
               a  word  by  the  forward-word, backward-word etc., editor com-
               mands.  If unset, `*?_-.[]~=' is used.


ENVIRONMENT

       AFSUSER (+)
               Equivalent to the afsuser shell variable.

       COLUMNS The number of columns in the terminal.   See  Terminal  manage-
               ment.

       DISPLAY Used by X Window System (see X(1)).  If set, the shell does not
               set autologout (q.v.).

       EDITOR  The pathname to a default editor.  See also the VISUAL environ-
               ment variable and the run-fg-editor editor command.

       GROUP (+)
               Equivalent to the group shell variable.

       HOME    Equivalent to the home shell variable.

       HPATH (+)
               A colon-separated list of directories  in  which  the  run-help
               editor command looks for command documentation.

       LANG    Gives the preferred character environment.  See Native Language
               System support.

       LC_CTYPE
               If set, only ctype character handling is changed.   See  Native
               Language System support.

       LINES   The  number of lines in the terminal.  See Terminal management.

       LS_COLORS
               The format of this variable is reminiscent  of  the  termcap(5)
               file  format; a colon-separated list of expressions of the form
               "xx=string", where "xx" is a two-character variable name.   The
               variables with their associated defaults are:

                   no   0      Normal (non-filename) text
                   fi   0      Regular file
                   di   01;34  Directory
                   ln   01;36  Symbolic link
                   pi   33     Named pipe (FIFO)
                   so   01;35  Socket
                   do   01;35  Door
                   bd   01;33  Block device
                   cd   01;32  Character device
                   ex   01;32  Executable file
                   mi   (none) Missing file (defaults to fi)
                   or   (none) Orphaned symbolic link (defaults to ln)
                   lc   ^[[    Left code
                   rc   m      Right code
                   ec   (none) End code (replaces lc+no+rc)

               You  need to include only the variables you want to change from
               the default.

               File names can also be colorized based on  filename  extension.
               This  is  specified  in the LS_COLORS variable using the syntax
               "*ext=string".  For example, using ISO 6429 codes, to color all
               C-language  source files blue you would specify "*.c=34".  This
               would color all files ending in .c in blue (34) color.

               Control characters can be  written  either  in  C-style-escaped
               notation,  or  in  stty-like  ^-notation.  The C-style notation
               adds ^[ for Escape, _ for a normal space character, and  ?  for
               Delete.   In  addition,  the ^[ escape character can be used to
               override the default interpretation of ^[, ^, : and =.

               Each file will be written as <lc> <color-code> <rc>  <filename>
               <ec>.   If  the  <ec> code is undefined, the sequence <lc> <no>
               <rc> will be used instead.  This is generally  more  convenient
               to  use,  but  less general.  The left, right and end codes are
               provided so you don't have to type common parts over  and  over
               again  and  to  support weird terminals; you will generally not
                       1   for brighter colors
                       4   for underlined text
                       5   for flashing text
                       30  for black foreground
                       31  for red foreground
                       32  for green foreground
                       33  for yellow (or brown) foreground
                       34  for blue foreground
                       35  for purple foreground
                       36  for cyan foreground
                       37  for white (or gray) foreground
                       40  for black background
                       41  for red background
                       42  for green background
                       43  for yellow (or brown) background
                       44  for blue background
                       45  for purple background
                       46  for cyan background
                       47  for white (or gray) background

               Not all commands will work on all systems or display devices.

               A few terminal programs do not recognize the default  end  code
               properly.   If all text gets colorized after you do a directory
               listing, try changing the no and fi codes from 0 to the numeri-
               cal codes for your standard fore- and background colors.

       MACHTYPE (+)
               The  machine  type  (microprocessor class or machine model), as
               determined at compile time.

       NOREBIND (+)
               If set, printable characters are not  rebound  to  self-insert-
               command.  See Native Language System support.

       OSTYPE (+)
               The operating system, as determined at compile time.

       PATH    A colon-separated list of directories in which to look for exe-
               cutables.  Equivalent to the path shell variable, but in a dif-
               ferent format.

       PWD (+) Equivalent  to  the cwd shell variable, but not synchronized to
               it; updated only after an actual directory change.

       REMOTEHOST (+)
               The host from which the user has logged in remotely, if this is
               the  case  and  the shell is able to determine it.  Set only if
               the shell was so compiled; see the version shell variable.

       SHLVL (+)
               Equivalent to the shlvl shell variable.

       SYSTYPE (+)
               The current system type.  (Domain/OS only)

       TERM    Equivalent to the term shell variable.
               EDITOR  environment  variable and the run-fg-editor editor com-
               mand.


FILES

       /etc/csh.cshrc  Read first by every shell.  ConvexOS, Stellix and Intel
                       use  /etc/cshrc  and  NeXTs  use /etc/cshrc.std.  A/UX,
                       AMIX, Cray and IRIX have no equivalent in  csh(1),  but
                       read  this  file  in tcsh anyway.  Solaris 2.x does not
                       have it either, but tcsh reads /etc/.cshrc.  (+)
       /etc/csh.login  Read by login shells after  /etc/csh.cshrc.   ConvexOS,
                       Stellix   and   Intel   use   /etc/login,   NeXTs   use
                       /etc/login.std, Solaris 2.x uses /etc/.login and  A/UX,
                       AMIX, Cray and IRIX use /etc/cshrc.
       ~/.tcshrc (+)   Read by every shell after /etc/csh.cshrc or its equiva-
                       lent.
       ~/.cshrc        Read by every shell, if ~/.tcshrc doesn't exist,  after
                       /etc/csh.cshrc  or  its  equivalent.   This manual uses
                       `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is  not
                       found, ~/.cshrc'.
       ~/.history      Read  by  login  shells  after ~/.tcshrc if savehist is
                       set, but see also histfile.
       ~/.login        Read by login shells  after  ~/.tcshrc  or  ~/.history.
                       The  shell  may  be  compiled  to  read ~/.login before
                       instead of after ~/.tcshrc and ~/.history; see the ver-
                       sion shell variable.
       ~/.cshdirs (+)  Read by login shells after ~/.login if savedirs is set,
                       but see also dirsfile.
       /etc/csh.logout Read by login shells at logout.  ConvexOS, Stellix  and
                       Intel  use  /etc/logout  and NeXTs use /etc/logout.std.
                       A/UX, AMIX, Cray and IRIX have no equivalent in csh(1),
                       but  read  this  file in tcsh anyway.  Solaris 2.x does
                       not have it either, but tcsh reads /etc/.logout.  (+)
       ~/.logout       Read by login shells at logout after /etc/csh.logout or
                       its equivalent.
       /bin/sh         Used  to  interpret  shell  scripts not starting with a
                       `#'.
       /tmp/sh*        Temporary file for `<<'.
       /etc/passwd     Source of home directories for `~name' substitutions.

       The order in which startup files are read may differ if the  shell  was
       so compiled; see Startup and shutdown and the version shell variable.


NEW FEATURES (+)

       This  manual  describes tcsh as a single entity, but experienced csh(1)
       users will want to pay special attention to tcsh's new features.

       A command-line editor, which supports  GNU  Emacs  or  vi(1)-style  key
       bindings.  See The command-line editor and Editor commands.

       Programmable,  interactive word completion and listing.  See Completion
       and listing and the complete and uncomplete builtin commands.

       Spelling correction (q.v.) of filenames, commands and variables.

       Editor commands (q.v.) which perform other useful functions in the mid-
       dle of typed commands, including documentation lookup (run-help), quick
       editor restarting (run-fg-editor) and  command  resolution  (which-com-
       Enhanced directory parsing and directory stack handling.  See  the  cd,
       pushd, popd and dirs commands and their associated shell variables, the
       description of Directory stack substitution, the dirstack, owd and sym-
       links shell variables and the normalize-command and normalize-path edi-
       tor commands.

       Negation in glob-patterns.  See Filename substitution.

       New File inquiry operators (q.v.) and a  filetest  builtin  which  uses
       them.

       A  variety  of  Automatic,  periodic  and timed events (q.v.) including
       scheduled events, special aliases, automatic logout and terminal  lock-
       ing, command timing and watching for logins and logouts.

       Support for the Native Language System (see Native Language System sup-
       port), OS variant features (see OS variant support and  the  echo_style
       shell variable) and system-dependent file locations (see FILES).

       Extensive terminal-management capabilities.  See Terminal management.

       New  builtin  commands including builtins, hup, ls-F, newgrp, printenv,
       which and where (q.v.).

       New variables that make useful  information  easily  available  to  the
       shell.   See  the  gid, loginsh, oid, shlvl, tcsh, tty, uid and version
       shell variables and the HOST, REMOTEHOST, VENDOR, OSTYPE  and  MACHTYPE
       environment variables.

       A new syntax for including useful information in the prompt string (see
       prompt).  and special prompts for loops and  spelling  correction  (see
       prompt2 and prompt3).

       Read-only variables.  See Variable substitution.


BUGS

       When  a  suspended command is restarted, the shell prints the directory
       it started in if this is different from the  current  directory.   This
       can be misleading (i.e., wrong) as the job may have changed directories
       internally.

       Shell  builtin  functions  are  not   stoppable/restartable.    Command
       sequences  of the form `a ; b ; c' are also not handled gracefully when
       stopping is attempted.  If you suspend `b', the shell will then immedi-
       ately  execute  `c'.   This  is especially noticeable if this expansion
       results from an alias.  It suffices to place the sequence  of  commands
       in ()'s to force it to a subshell, i.e., `( a ; b ; c )'.

       Control  over tty output after processes are started is primitive; per-
       haps this will inspire someone to  work  on  a  good  virtual  terminal
       interface.   In  a  virtual  terminal  interface  much more interesting
       things could be done with output control.

       Alias substitution is most often used to clumsily simulate shell proce-
       dures; shell procedures should be provided rather than aliases.

       Commands  within  loops  are  not  placed in the history list.  Control
       The  screen  update for lines longer than the screen width is very poor
       if the terminal cannot move the cursor up (i.e., terminal type `dumb').

       HPATH and NOREBIND don't need to be environment variables.

       Glob-patterns  which  do  not use `?', `*' or `[]' or which use `{}' or
       `~' are not negated correctly.

       The single-command form of if  does  output  redirection  even  if  the
       expression is false and the command is not executed.

       ls-F includes file identification characters when sorting filenames and
       does not handle control characters in filenames  well.   It  cannot  be
       interrupted.

       Report bugs to tcsh-bugs@mx.gw.com, preferably with fixes.  If you want
       to help maintain and test tcsh, send mail  to  listserv@mx.gw.com  with
       the  text `subscribe tcsh <your name>' on a line by itself in the body.
       You can also `subscribe tcsh-bugs <your name>' to get all bug  reports,
       or  `subscribe tcsh-diffs <your name>' to get the development list plus
       diffs for each patchlevel.


THE T IN TCSH

       In 1964, DEC produced the PDP-6.  The PDP-10 was a later re-implementa-
       tion.   It  was  re-christened  the DECsystem-10 in 1970 or so when DEC
       brought out the second model, the KI10.

       TENEX was created at Bolt, Beranek & Newman (a Cambridge, Massachusetts
       think  tank)  in  1972  as an experiment in demand-paged virtual memory
       operating systems.  They built a new pager for the DEC PDP-10 and  cre-
       ated the OS to go with it.  It was extremely successful in academia.

       In  1975,  DEC  brought  out  a new model of the PDP-10, the KL10; they
       intended to have only a version of TENEX, which they had licensed  from
       BBN,  for  the new box.  They called their version TOPS-20 (their capi-
       talization is trademarked).  A lot of  TOPS-10  users  (`The  OPerating
       System  for PDP-10') objected; thus DEC found themselves supporting two
       incompatible systems on the same hardware--but then there were 6 on the
       PDP-11!

       TENEX,  and  TOPS-20  to  version 3, had command completion via a user-
       code-level subroutine library called ULTCMD.  With version 3, DEC moved
       all  that  capability  and more into the monitor (`kernel' for you Unix
       types), accessed by the COMND% JSYS (`Jump to SYStem' instruction,  the
       supervisor call mechanism [are my IBM roots also showing?]).

       The creator of tcsh was impressed by this feature and several others of
       TENEX and TOPS-20, and created a version of csh which mimicked them.


LIMITATIONS

       Words can be no longer than 1024 characters.

       The system limits argument lists to 10240 characters.

       The number of arguments to a command which involves filename  expansion
       is  limited  to  1/6th  the number of characters allowed in an argument
       list.
       tset(1),   vi(1),   x(1),  access(2),  execve(2),  fork(2),  killpg(2),
       pipe(2), setrlimit(2), sigvec(2), stat(2), umask(2), vfork(2), wait(2),
       malloc(3),  setlocale(3),  tty(4),  a.out(5),  termcap(5),  environ(7),
       termio(7), Introduction to the C Shell


VERSION

       This manual documents tcsh 6.12.00 (Astron) 2002-07-23.


AUTHORS

       William Joy
         Original author of csh(1)
       J.E. Kulp, IIASA, Laxenburg, Austria
         Job control and directory stack features
       Ken Greer, HP Labs, 1981
         File name completion
       Mike Ellis, Fairchild, 1983
         Command name recognition/completion
       Paul Placeway, Ohio State CIS Dept., 1983-1993
         Command line editor, prompt routines, new glob  syntax  and  numerous
         fixes and speedups
       Karl Kleinpaste, CCI 1983-4
         Special  aliases,  directory  stack  extraction  stuff,  login/logout
         watch, scheduled events, and the idea of the new prompt format
       Rayan Zachariassen, University of Toronto, 1984
         ls-F and which builtins and numerous  bug  fixes,  modifications  and
         speedups
       Chris Kingsley, Caltech
         Fast storage allocator routines
       Chris Grevstad, TRW, 1987
         Incorporated 4.3BSD csh into tcsh
       Christos S. Zoulas, Cornell U. EE Dept., 1987-94
         Ports   to   HPUX,   SVR2  and  SVR3,  a  SysV  version  of  getwd.c,
         SHORT_STRINGS support and a new version of sh.glob.c
       James J Dempsey, BBN, and Paul Placeway, OSU, 1988
         A/UX port
       Daniel Long, NNSC, 1988
         wordchars
       Patrick Wolfe, Kuck and Associates, Inc., 1988
         vi mode cleanup
       David C Lawrence, Rensselaer Polytechnic Institute, 1989
         autolist and ambiguous completion listing
       Alec Wolman, DEC, 1989
         Newlines in the prompt
       Matt Landau, BBN, 1989
         ~/.tcshrc
       Ray Moody, Purdue Physics, 1989
         Magic space bar history expansion
       Mordechai ????, Intel, 1989
         printprompt() fixes and additions
       Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
         Automatic spelling correction and prompt3
       Per Hedeland, Ellemtel, Sweden, 1990-
         Various bugfixes, improvements and manual updates
       Hans J. Albertsson (Sun Sweden)
         ampm, settc and telltc
       Michael Bloom
         Interrupt handling fixes

       Johan Widen, SICS Sweden, 1990
         shlvl, Mach support, correct-line, 8-bit printing
       Matt Day, Sanyo Icon, 1990
         POSIX termio support, SysV limit fixes
       Jaap Vermeulen, Sequent, 1990-91
         Vi mode fixes, expand-line, window change fixes, Symmetry port
       Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
         autolist  beeping  options, modified the history search to search for
         the whole string from the beginning of the line to the cursor.
       Scott Krotz, Motorola, 1991
         Minix port
       David Dawes, Sydney U. Australia, Physics Dept., 1991
         SVR4 job control fixes
       Jose Sousa, Interactive Systems Corp., 1991
         Extended vi fixes and vi delete command
       Marc Horowitz, MIT, 1991
         ANSIfication fixes, new exec hashing code, imake fixes, where
       Bruce Sterling Woodcock, sterling@netcom.com, 1991-1995
         ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n  addition,
         and various other portability changes and bug fixes
       Jeff Fink, 1992
         complete-word-fwd and complete-word-back
       Harry C. Pulley, 1992
         Coherent port
       Andy Phillips, Mullard Space Science Lab U.K., 1992
         VMS-POSIX port
       Beto Appleton, IBM Corp., 1992
         Walking  process  group fixes, csh bug fixes, POSIX file tests, POSIX
         SIGHUP
       Scott Bolte, Cray Computer Corp., 1992
         CSOS port
       Kaveh R. Ghazi, Rutgers University, 1992
         Tek, m88k, Titan and Masscomp ports and fixes.  Added  autoconf  sup-
         port.
       Mark Linderman, Cornell University, 1992
         OS/2 port
       Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
         Linux port
       Tim P. Starrin, NASA Langley Research Center Operations, 1993
         Read-only variables
       Dave Schweisguth, Yale University, 1993-4
         New man page and tcsh.man2html
       Larry Schwimmer, Stanford University, 1993
         AFS and HESIOD patches
       Luke Mewburn, RMIT University, 1994-6
         Enhanced directory printing in prompt, added ellipsis and rprompt.
       Edward Hutchins, Silicon Graphics Inc., 1996
         Added implicit cd.
       Martin Kraemer, 1997
         Ported to Siemens Nixdorf EBCDIC machine
       Amol Deshpande, Microsoft, 1997
         Ported  to  WIN32  (Windows/95 and Windows/NT); wrote all the missing
         library and message catalog code to interface to Windows.
       Taga Nayuta, 1998
         Color ls additions.


Astron 6.12.00                   23 July 2002                          tcsh(1)