TCSH(1) TCSH(1)
tcsh - shell with file name completion and command line editing
tcsh [ -bcdefimnqstvVxX ] [ argument ... ]
or
tcsh -l
OS/Dependent Options
tcsh [ -F ] [ -Dname[=value] ]
Tcsh is an enhanced version of the Berkeley UNIX C shell csh(1). It
behaves similarly to the C shell, except for the added utilities of:
1) Command line editing using Emacs-style commands.
2) Visual step up/down through the history list.
3) Terminal mode sanity checking and resetting.
4) Interactive command, file name and user name completion.
5) File/directory/user list in the middle of a typed command.
6) Spelling correction of command, file, and user names.
7) Lookup of command documentation in the middle of a typed command.
8) Enhanced history mechanism.
9) Automatic locking/logout after long periods of idle time.
10) Automatic execution of a single command prior to printing each
prompt.
11) Automatic periodic command execution.
12) A new syntax for the prompt, and the ability to set the prompt for
"while" and "for" loops.
13) Time stamps in the history list.
14) An addition to the syntax of filenames to access entries in the
directory stack, and the ability treat symbolic links in a sane way
when changing directories.
15) The ability to watch for logins and logouts by user or terminal on
the machine.
16) A scheduled event list, which specifies commands which are to be
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executed at given times.
17) A new builtin that does a subset of ls(1).
18) An addition to the file expression syntax for a character not in a
set of characters and the ability to negate a globbing pattern.
19) New automatically initialized environment variables HOST and
HOSTTYPE.
20) Commands for debugging terminal capabilities.
21) Searching for the visual history mechanism.
22) New builtins for the which(1) and where commands.
23) Restarting a stopped editor with two keystrokes.
24) Status line support
25) Automatic execution of a command when the current working directory
is changed.
26) Native Language System support.
27) Automatic process time reporting.
28) OS Dependent Builtin Support
29) Automatic window size adjustment
30) Input files
31) Additional/Undocumented Options
32) Enhanced history/variable modifier expansion
33) Programmable completion.
34) Enhanced file inquiry operator.
35) Readonly variables.
36) Implicit cd for directory names entered as commands.
For a description of standard C-shell features, see the csh manual page.
1. COMMAND LINE EDITING
Commands that the user types in may be edited using the same control
characters that Gnu Emacs or vi uses. Arrow and function key sequences
are also allowed. Tcsh allows this by setting the terminal to `CBREAK'
mode and reading the input one character at a time.
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There is a new shell command, bindkey, that allows the user to redefine
what any key does, or find out what any or all of the keys do.
Syntax: bindkey [ -a ] [ -c ] [ -s ] [ -v ] [ -e ] [ -d ] [ -k ] [ -l ] [
-r ] [ -- ] [ [ in-string | key-name ] [ out-string | command ]]
If no values are given all bindings are listed. If only in-string is
given, bindings for the in-string is listed.
Otherwise it binds the in-string to the given out-string or command. If
out-string, this is treated as input to tcsh when in-string is typed.
This may be used recursively to currently a level of 10 deep.
There are two basic key maps: the normal and alternative one. The
alternative is used by VI command mode. For multi-character input the
basic key maps contains a sequence-lead-in for the first character in the
input.
Options:
-a bind in-string in alternative key map
-s bind an out-string instead of a command
-c bind a unix command instead of a command
-v bind for default VI-mode
-e bind for default emacs-mode
-k interpret in-string as a symbolic arrow key name
-d bind to compiled in default
-l list functions available with short description
-r remove the binding of in-string
In strings control characters may be written as caret-<letter> and
backslash ("\") is used to escape a character as follows:
\a bell character
\n line feed (new line)
\b back space
\t horizontal tab
\v vertical tab
\f form feed
\r carriage return
\e escape
\nnn character code in octal
In all other cases \ escapes the following character. Needed for escaping
the special meaning of \ and ^. Delete is written as "^?" (caretquestion
mark).
Tcsh always binds the arrow keys as defined by the termcap entry to:
up arrow up-history
down arrow down-history
right arrow forward-char
left arrow backward-char
except where these bindings would alter other single character bindings.
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If this is not desired one can avoid the automatic arrow key binding
using settc to change the arrow key escape sequences to the empty string.
The ansi/vt100 sequences for arrow keys are always bound.
The following is a list of the default emacs and vi bindings. Characters
with the 8th bit set are written as M-<character>. Note however, that
unlike with the old bind command (see below), the syntax M-<character>
has no special meaning to the bindkey command, and the bindings for the
sequence escape+<character> and M-<character> as given below are handled
separately (although the default bindings are the same). The printable
ascii characters not mentioned in the list are bound to the self-insert-
command function, which just inserts the given character literally into
the input line. The remaining characters are bound to the undefined-key
function, which only causes a beep (unless nobeep is set, of course).
EMACS bindings
"^@" -> set-mark-command
"^A" -> beginning-of-line
"^B" -> backward-char
"^C" -> tty-sigintr
"^D" -> delete-char-or-list
"^E" -> end-of-line
"^F" -> forward-char
"^G" -> is undefined
"^H" -> backward-delete-char
"^I" -> complete-word
"^J" -> newline
"^K" -> kill-line
"^L" -> clear-screen
"^M" -> newline
"^N" -> down-history
"^O" -> tty-flush-output
"^P" -> up-history
"^Q" -> tty-start-output
"^R" -> redisplay
"^S" -> tty-stop-output
"^T" -> transpose-chars
"^U" -> kill-whole-line
"^V" -> quoted-insert
"^W" -> kill-region
"^X" -> sequence-lead-in
"^Y" -> yank
"^Z" -> tty-sigtsusp
"^[" -> sequence-lead-in
"^\" -> tty-sigquit
"^]" -> tty-dsusp
" " to "/" -> self-insert-command
"0" to "9" -> digit
":" to "~" -> self-insert-command
"^?" -> backward-delete-char
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EMACS Multi-character and 8 bit bindings
"^[^D" or "M-^D" -> list-choices
"^[^H" or "M-^H" -> backward-delete-word
"^[^I" or "M-^I" -> complete-word
"^[^L" or "M-^L" -> clear-screen
"^[^Z" or "M-^Z" -> run-fg-editor
"^[^[" or "M-^[" -> complete-word
"^[^_" or "M-^_" -> copy-prev-word
"^[ " or "M- " -> expand-history
"^[!" or "M-!" -> expand-history
"^[$" or "M-$" -> spell-line
"^[0" or "M-0" -> digit-argument
"^[1" or "M-1" -> digit-argument
"^[2" or "M-2" -> digit-argument
"^[3" or "M-3" -> digit-argument
"^[4" or "M-4" -> digit-argument
"^[5" or "M-5" -> digit-argument
"^[6" or "M-6" -> digit-argument
"^[7" or "M-7" -> digit-argument
"^[8" or "M-8" -> digit-argument
"^[9" or "M-9" -> digit-argument
"^[?" or "M-?" -> which-command
"^[B" or "M-B" -> backward-word
"^[C" or "M-C" -> capitalize-word
"^[D" or "M-D" -> delete-word
"^[F" or "M-F" -> forward-word
"^[H" or "M-H" -> run-help
"^[L" or "M-L" -> downcase-word
"^[N" or "M-N" -> history-search-forward
"^[P" or "M-P" -> history-search-backward
"^[R" or "M-R" -> toggle-literal-history
"^[S" or "M-S" -> spell-word
"^[U" or "M-U" -> upcase-word
"^[W" or "M-W" -> copy-region-as-kill
"^[_" or "M-_" -> insert-last-word
"^[b" or "M-b" -> backward-word
"^[c" or "M-c" -> capitalize-word
"^[d" or "M-d" -> delete-word
"^[f" or "M-f" -> forward-word
"^[h" or "M-h" -> run-help
"^[l" or "M-l" -> downcase-word
"^[n" or "M-n" -> history-search-forward
"^[p" or "M-p" -> history-search-backward
"^[r" or "M-r" -> toggle-literal-history
"^[s" or "M-s" -> spell-word
"^[u" or "M-u" -> upcase-word
"^[w" or "M-w" -> copy-region-as-kill
"^[^?" or "M-^?" -> backward-delete-word
"^X^X" -> exchange-point-and-mark
"^X*" -> expand-glob
"^X$" -> expand-variables
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"^XG" -> list-glob
"^Xg" -> list-glob
"^Xn -> normalize-path
"^XN -> normalize-path
VI Insert Mode functions
"^@" -> is undefined
"^A" -> beginning-of-line
"^B" -> backward-char
"^C" -> tty-sigintr
"^D" -> list-or-eof
"^E" -> end-of-line
"^F" -> forward-char
"^G" -> list-glob
"^H" -> backward-delete-char
"^I" -> complete-word
"^J" -> newline
"^K" -> kill-line
"^L" -> clear-screen
"^M" -> newline
"^N" -> down-history
"^O" -> tty-flush-output
"^P" -> up-history
"^Q" -> tty-start-output
"^R" -> redisplay
"^S" -> tty-stop-output
"^T" -> transpose-chars
"^U" -> backward-kill-line
"^V" -> quoted-insert
"^W" -> backward-delete-word
"^X" -> expand-line
"^Y" -> tty-dsusp
"^Z" -> tty-sigtsusp
"^[" -> vi-cmd-mode
"^\" -> tty-sigquit
" " to "~" -> self-insert-command
"^?" -> backward-delete-char
VI Command Mode functions
"^@" -> is undefined
"^A" -> beginning-of-line
"^B" -> is undefined
"^C" -> tty-sigintr
"^D" -> list-choices
"^E" -> end-of-line
"^F" -> is undefined
"^G" -> list-glob
"^H" -> backward-char
"^I" -> vi-cmd-mode-complete
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"^J" -> newline
"^K" -> kill-line
"^L" -> clear-screen
"^M" -> newline
"^N" -> down-history
"^O" -> tty-flush-output
"^P" -> up-history
"^Q" -> tty-start-output
"^R" -> redisplay
"^S" -> tty-stop-output
"^T" -> is undefined
"^U" -> backward-kill-line
"^V" -> is undefined
"^W" -> backward-delete-word
"^X" -> expand-line
"^[" -> sequence-lead-in
"^\" -> tty-sigquit
" " -> forward-char
"!" -> expand-history
"$" -> end-of-line
"*" -> expand-glob
"+" -> down-history
";" -> vi-repeat-char-fwd
"," -> vi-repeat-char-back
"-" -> up-history
"." -> is undefined
"/" -> vi-search-back
"0" -> vi-zero
"1" to "9" -> digit-argument
"?" -> vi-search-fwd
"@" -> is undefined
"A" -> vi-add-at-eol
"B" -> vi-word-back
"C" -> change-till-end-of-line
"D" -> kill-line
"E" -> vi-endword
"F" -> vi-char-back
"I" -> vi-insert-at-bol
"J" -> history-search-forward
"K" -> history-search-backward
"N" -> vi-search-back
"O" -> sequence-lead-in
"R" -> vi-replace-mode
"S" -> vi-substitute-line
"T" -> vi-charto-back
"U" -> is undefined
"V" -> expand-variables
"W" -> vi-word-fwd
"X" -> backward-delete-char
"[" -> sequence-lead-in
"\^" -> beginning-of-line
"a" -> vi-add
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"b" -> backward-word
"c" -> is undefined
"d" -> vi-delmeta
"e" -> vi-eword
"f" -> vi-char-fwd
"h" -> backward-char
"i" -> vi-insert
"j" -> down-history
"k" -> up-history
"l" -> forward-char
"m" -> is undefined
"n" -> vi-search-fwd
"r" -> vi-replace-char
"s" -> vi-substitute-char
"t" -> vi-charto-fwd
"u" -> vi-undo
"v" -> expand-variables
"w" -> vi-beginning-of-next-word
"x" -> delete-char
"~" -> change-case
"^?" -> backward-delete-char
"M-?" -> run-help
"M-[" -> sequence-lead-in
"M-O" -> sequence-lead-in
VI Multi-character bindings
"^[?" -> run-help
In tcsh there are two input modes: insert and overwrite. All characters
that are bound to the self-insert-command either get inserted or
overwrite what was under the cursor depending on the input mode. In emacs
one can toggle between modes using the overwrite-mode function, and in VI
one can use any of the replace mode commands. By default the mode is
preserved between input lines. To specify a default mode that can be
enforced at the beginning of each command line, the variable inputmode
can be set to either insert or overwrite.
There is also an older version of bindkey called bind, that allows the
user to redefine what any key does, or find out what any or all of the
keys do. This is retained for compatibility reasons.
If given two arguments bind binds the function (first argument) to the
given key (second argument). The key may be: the direct character or a
caret-<letter> combination, which is converted to control-<letter>; M<letter>
for an escaped character; or F-<string> for a function key. For
the last of these, the function key prefix must be bound to the function
"sequence-lead-in" and the string specified to the bind command must not
include this prefix.
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If given one argument bind takes the argument as the name for a key and
tells what that key does. As a special case, the user can say
bind emacs
or
bind vi
to bind all the keys for Emacs or vi mode respectively.
If given no arguments bind tells what all of the keys do. If you give
bind the single argument of 'defaults', it resets each key to its default
value (see the above list).
2. VISUAL HISTORY
The keys ^P and ^N are used to step up and down the history list. If the
user has typed in the following:
> ls
foo bar
> echo mumble
mumble
>
then enters ^P, the shell will place "echo mumble" into the editing
buffer, and will put the cursor at the end of the line. If another ^P is
entered, then the editing line will change to "ls". More ^Ps will make
the bell ring, since there are no more lines in the history. ^N works
the same way, except it steps down (forward in time).
An easy way to re-do a command is to type ^P followed by Return. Also,
pieces of previous commands can be assembled to make a new command. The
commands that work on regions are especially useful for this.
^P and ^N actually only copy commands from out of the history into the
edit buffer; thus the user may step back into the history and then edit
things, but those changes do not affect what is actually in tcsh 's
history.
Another way to recall (parts of) history commands is via the 'expandhistory'
function. A variation of the 'expand-history' function is called
'magic-space'. This function expands csh history, and always appends a
space. Magic-space thus can be bound to <space>, to automatically expand
csh history. Expand-history is normally bound to M-<space> and magicspace
is not bound.
3. TTY MODE SANITY
As part of the editor, tcsh does a check and reset of the terminal mode
bits. If the speed has been changed, then tcsh will change to using that
speed. Tcsh will also obey changes in the padding needed by the tty.
Also, the shell will automatically turn off RAW and CBREAK (on systems
that use termio(7) it will turn on ICANON) modes, and will turn on the
tty driver's output processing (OPOST).
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The list of the tty modes that are always set or cleared by tcsh can be
examined and modified using the setty builtin. The setty display is
similar to stty(1), and varies depending on the system's tty driver.
Modes that tcsh will always try to set are shown as +mode . Modes that
tcsh will always try to clear are shown as -mode and modes that tcsh will
track and allow to be modified are not shown by default, or if the -a
flag is given, are shown without a leading sign. For tty characters, -
char disables the tty character, while +char protects the tty character
from being changed.
Setty can be used to control the three different modes tcsh uses for the
tty. The default mode displayed is the "execute" mode which is used when
tcsh executes commands. The two other modes are the "edit" mode and the
"quote" mode. The "edit" mode is used for command line editing, and the
"quote" mode is used when entering literal characters. The "execute" mode
can be specified with -x , the "edit" mode with -d , and the "quote" mode
with -q For example if one wants to set the echok flag and let the echoe
pass unchanged:
> setty
iflag:-inlcr -igncr +icrnl
oflag:+opost +onlcr -onlret
cflag:
lflag:+isig +icanon +echo +echoe -echok -echonl -noflsh
+echoctl -flusho +iexten
chars:
> setty +echok echoe
> setty
iflag:-inlcr -igncr +icrnl
oflag:+opost +onlcr -onlret
cflag:
lflag:+isig +icanon +echo +echok -echonl -noflsh +echoctl
-flusho +iexten
chars:
4. WORD COMPLETION
In typing commands, it is no longer necessary to type a complete name,
only a unique abbreviation is necessary. When you type a TAB to tcsh it
will complete the name for you, echoing the full name on the terminal
(and entering it into the edit buffer). If the prefix you typed matches
no name, the terminal bell is rung, unless the variable nobeep is set.
The name may be partially completed if the prefix matches several longer
names. If this is the case, the name is extended up to the point of
ambiguity, and the bell is rung. This works for file names, command
names, shell variables and the ~ user name convention. The variable
fignore may be set to a list of suffixes to be disregarded during
completion.
Example
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Assume the current directory contained the files:
DSC.TXT bin cmd lib memos
DSC.NEW chaos cmtest mail netnews
bench class dev mbox new
The command:
> gnumacs ch[TAB]
would cause tcsh to complete the command with the file name chaos. If
instead, the user had typed:
> gnumacs D[TAB]
tcsh would have extended the name to DSC and rung the terminal bell,
indicating partial completion. However, if fignore had previously been
set to a list containing .NEW as one element, e.g. ( .o .NEW ), tcsh
would have completed the `D' to DSC.TXT.
File name completion works equally well when other directories are
addressed. Additionally, tcsh understands the C shell tilde (~)
convention for home directories. In addition it caches tilde name
references for fast access. This cache can be flushed by using the
builtin rehash. Thus,
> cd ~speech/data/fr[TAB]
does what one might expect. This may also be used to expand login names
only. Thus,
> cd ~sy[TAB]
expands to
> cd ~synthesis
Command names may also be completed, for example,
> gnum[TAB]
will expand to "gnumacs" (assuming that there are no other commands that
begin with "gnum").
Shell and environment variables are recognized also and in addition they
can be expanded:
> set local=/usr/local
> echo $lo[TAB]
will expand to "$local/". Note that a slash is appended because the
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expanded variable points to a directory. Also:
> set local=/usr/local
> echo $local/[^D]
bin/ etc/ lib/ man/ src/
will correctly list the contents of /usr/local. Shell and environment
variables can also be expanded via the expand-variables function:
> echo $local/[^X$]
> echo /usr/local/
Completion also works when the cursor is in the middle of the line,
rather than just the end. All of the text after the cursor will be
saved, the completion will work (possibly adding to the current name),
and then the saved text will be restored in place, after the cursor.
The behavior of the completion can be changed by the setting of several
shell variables:
Setting the recexact variable makes an exact command be expanded rather
than just ringing the bell. For example, assume the current directory
has two sub-directories called foo and food, then with recexact set the
following could be done:
> cd fo[TAB]
to ...
> cd foo[TAB]
to ...
> cd foo/
rather than beeping on the second TAB.
If the autolist variable is set, invoking completion when several choices
are possible will automatically list the choices, effectively merging the
functionality described in the next section into the completion
mechanism. If autolist is set to "ambiguous", then tcsh will only list
the choices if there were no new characters added in the completion
operation.
The "noise level" can be controlled by the value that matchbeep is set
to: With matchbeep=nomatch, completion will only beep if there are no
matching names; with matchbeep=ambiguous, completion will also beep if
there are many possible matches; with matchbeep=notunique, completion
will also beep when there is an exact match but there are other, longer,
matches (see recexact). With matchbeep=never or set to any other value
completion will never beep. If matchbeep is not set it defaults to
ambiguous.
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If the autoexpand variable is set, the expand-history function will be
invoked automatically before the completion attempt, expanding normal csh
history substitutions.
For covert operation, the variable nobeep can be set; it will prevent the
completion mechanism, as well as tcsh in general, from actually beeping.
Finally, if the autocorrect variable is set, the spelling correction is
attempted for any path components up to the completion point.
5. LISTING OF POSSIBLE NAMES
At any point in typing a command, you may request "what names are
available". Thus, when you have typed, perhaps:
> cd ~speech/data/fritz/
you may wish to know what files or sub-directories exist (in
~speech/data/fritz), without, of course, aborting the command you are
typing. Typing the character Control-D (^D), will list the names (files,
in this case) available. The files are listed in multicolumn format,
sorted column-wise. Directories are indicated with a trailing `/',
executable files with a `*', symbolic links with a '@', sockets with a
'=', FIFOs (named pipes) with a '|', character devices with a '%', and
block devices with a '#'. Once printed, the command is re-echoed for you
to complete.
Additionally, one may want to know which files match a prefix. If the
user had typed:
> cd ~speech/data/fr[^D]
all files and sub-directories whose prefix was ``fr'' would be printed.
Notice that the example before was simply a degenerate case of this with
a null trailing file name. (The null string is a prefix of all strings.)
Notice also, that a trailing slash is required to pass to a new directory
for both file name completion and listing.
The degenerate
> ~[^D]
will print a full list of login names on the current system. Note,
however, that the degenerate
> <Spaces>[^D]
does not list all of the commands, but only the files in the current
working directory.
Listing/expanding of words that match a name containing wildcard
characters can be done via the list-glob/expand-glob function:
> ls
foo.c bar.c a.out
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> vi *.c[^Xg]
foo.c bar.c
> vi *.c[^X*]
> vi foo.c bar.c
Command Name Recognition
Command name recognition and completion works in the same manner as file
name recognition and completion above. The current value of the
environment variable PATH is used in searching for the command. For
example
> newa[TAB]
might expand to
> newaliases
Also,
> new[^D]
would list all commands (along PATH) that begin with "new".
Note that Control-D has three different effects on tcsh. On an empty line
(one that contains nothing, not even spaces), ^D sends an EOF to tcsh
just as it does for normal programs. When the cursor is in the middle of
a line of text, ^D deletes the character that the cursor is under.
Finally, a ^D at the end of a line of text lists the available names at
that point. To get a list of available names when the cursor is in the
middle of a line (or on an empty line), a Meta-Control-D should be typed
(Escape followed by Control-D).
6. SPELLING CORRECTION
If while typing a command, the user mistypes or misspells a file name,
user name, or command name, tcsh can correct the spelling. When
correcting a file name, each part of the path is individually checked and
corrected. Spelling correction can be invoked in several different ways:
The spell-word function, normally bound to M-s (and M-S), will attempt to
correct the word immediately before the cursor. For example, suppose
that the user has typed:
> cd /uxr/spol/news[ESC s]
Tcsh will check the path for spelling, correct the mistakes, and redraw
the line as
> cd /usr/spool/news
leaving the cursor at the end of the line.
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Spelling correction of the entire command line (independent of where the
cursor is) can be done with the spell-line function, normally bound to
M-$ (Escape Dollar-sign). It will check each word independently, but in
order to avoid e.g. command options, no correction is attempted on words
whose first character is found in the string "!.\^-*%".
Finally, automatic spelling correction will be done each time the Return
key is hit, if the correct variable is set to an appropriate value:
correct=cmd will cause the spelling of the command name only to be
checked, while correct=all causes checking of all words on the line, like
the spell-line function. If any part of the command line is corrected,
the user will be given a special prompt as defined by the prompt3
variable, followed by the corrected line, e.g.
> lz /usr/bin
CORRECT>ls /usr/bin (y|n|e)?
Answering 'y' or <space> at the prompt will cause the corrected line to
be executed, 'e' will leave the uncorrected command in the input buffer
and anything else will execute the original line unchanged.
Automatic correction is not guaranteed to work the way the user intended.
Command line parsing is done in a rudimentary fashion. It is mostly
provided as an experimental feature. Suggestions and improvements are
welcome.
7. DOCUMENTATION LOOKUP
The editor function run-help (M-h) prints a help file on the current
command (using the same definition of current as the completion routines
use). This help file is found by searching the path list HPATH for files
of the form foo.help, foo.1, foo.8, or foo.6 in that order (assuming that
the current command is foo). The file is just printed, not paged in any
way. This is because run-help is meant to be used to look up short help
files, not manual pages (although it can do manual pages also).
8. ENHANCED HISTORY MECHANISM
Tcsh will save the history list between login sessions. It does this by
writing the current list to the file "~/.history" on logout, and reading
it in on login. For example, placing the line
> set history=25 savehist=20
tells tcsh to save the last 25 commands on the history list, and to save
the last 20 of them between logins. The "savehist" variable may be set
up to the size of history, although it is an error to have savehist
larger than history. In addition to the above tcsh, keeps unparsed
(literal) versions of the history if the variable histlit is set. Also
the toggle-history function toggles between the parsed and literal
version of the recalled history in the editor buffer. For example:
> set histlit
> echo !:s/foo/bar; ls
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Modifier failed.
> ^P
> echo !:s/foo/bar; ls
> unset histlit
> echo !:s/foo/bar; ls
Modifier failed.
> ^P
> echo unset histlit[M-r]
> echo !:s/foo/bar; ls
Tcsh also supports the history escape !#. This undocumented csh escape
holds the words of the current line. This is useful in renaming commands:
> mv foo bar!#:1
mv foo barfoo
Care should be taken when using this history expansion in csh since there
is no check for recursion. In tcsh up to 10 levels of recursion are
allowed.
Another difference between tcsh and csh history expansion, is the
treatment of history arguments. In csh !3d expands to event 3 with the
letter "d" appended to it. There is no way to repeat a command that
begins with a number using the name of the command in the history escape.
In tcsh only numeric arguments are treated as event numbers; therefore
!3d is interpreted as: repeat the last command that started with the
string "3d". To mimic the csh behavior !3\d can be used.
9. AUTOMATIC LOGOUT/LOCKING
The automatic locking and logout time are controlled by the variable
autologout. The value of the first word is the number of minutes of
inactivity will be allowed before automatically logging the user out.
When that many minutes have been reached, the shell prints "auto-logout"
and dies (without executing ~/.logout). The default for tcsh is to set
autologout for 60 minutes on login shells, and when the user is root. To
disable autologout (for instance in a window system), unset the shell
variable autologout.
The value of the optional second word indicates the number of minutes of
inactivity after which the user will be prompted for his login password
to continue working. Failure to enter the correct password 5 times,
results in auto-logout.
10. EXECUTION OF A COMMAND PRIOR TO EACH PROMPT
Tcsh supports a special alias, precmd, which if set holds a command that
will be executed before printing each prompt. For example, if the user
has done
> alias precmd date
then the program date will be run just before the shell prompts for each
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command. There are no limitations on what precmd can be set to do,
although discretion should be used.
11. PERIODIC COMMAND EXECUTION
Tcsh is now capable of providing periodic command execution through the
use of the shell variable tperiod and the alias periodic. When these
items are set, the alias periodic will be executed every tperiod minutes.
This provides a convenient means for checking on common but infrequent
changes, such as new messages. Example:
> set tperiod = 30
> alias periodic checknews
This will cause the checknews(1) program to be run every 30 minutes.
Having the alias periodic set but with an unset tperiod (or a value of 0
for tperiod) will cause periodic to degenerate to another form of precmd.
12. NEW PROMPT FORMAT
The format for the prompt shell variable has been changed to include many
new things, such as the current time of day, current working directory,
etc. The new format uses "%<char>" to signal an expansion, much like
printf(3S). The available sequences are:
%/ Current working directory.
%~ cwd. If it starts with $HOME, that part is
replaced by a ~. In addition if a directory
name prefix matches a user's home directory,
that part of the directory will be substituted
with ~user. NOTE: The ~user substitution will
only happen if the shell has performed a ~
expansion for that user name in this session.
%c or %. Trailing component of cwd, may be
followed by a digit to get more than one
component, if it starts with $HOME, that
part is replaced with a ~.
%C Trailing component of cwd, may be followed
by a digit to get more than one component, no
~ substitution.
%h, %!, ! Current history event number.
%M The full machine hostname.
%m The hostname up to the first ".".
%S (%s) Start (stop) standout mode.
%B (%b) Start (stop) boldfacing mode. (Only if
tcsh was compiled to be eight bit clean.)
%U (%u) Start (stop) underline mode. (Only if
tcsh was compiled to be eight bit clean.)
%t or %@ Current time of day, in 12-hour, am/pm format.
%T Current time of day, in 24-hour format.
(But see the ampm shell variable below.)
%p Current time in 12-hour format, am/pm format with seconds.
%P Current time in 24-hour format, with seconds.
\c `c' is parsed the same way as in bindkey.
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^c `c' is parsed the same way as in bindkey.
%% A single %.
%n The user name, contents of $user.
%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 line (tty) the user is logged on.
%L clear from prompt to end of display or end of line.
%# A `#' if tcsh is run as a root shell,
a `>' if not.
%{..%} Include string as a literal escape sequence.
Note that the enclosed escape sequence, should
only be used to change terminal attributes and
should not move the cursor location. Also, this
cannot be the last character in the prompt
string. (Available only if tcsh was compiled to
be eight bit clean.)
%? return code of the last command executed just
before the prompt.
%R In prompt3 this is the corrected string; in
prompt2 it is the status of the parser.
On %C, %c and %., if the optional digit is 0, then the next digit is
interpreted as the number of directory components to be skipped, and the
number of components skipped are reported as: /<num-skipped>path/path.
The sequences for standout are often used to indicate that this is an
enabled (running as root) shell. An example:
> set prompt="%m [%h] %U[%@]%u [%/] you rang? "
tut [37] [2:54pm] [/usr/accts/sys] you rang? _
In addition, there is a new variable, prompt2, which is used to prompt
for the body of while and for loops (wherever normal csh prompts with a
question mark). The default for prompt2 is "%R? ": the status of the
parser followed by a question mark. This alternate prompt is also used
when the parser is waiting for more input; i.e. when the previous line
ended in a \. The prompt3 variable is used when displaying the corrected
command line when automatic spelling correction is in effect; it defaults
to "CORRECT>%R (y|n|e)? ".
13. TIME-STAMPED HISTORY LIST
The history list in tcsh now has a time-of-day stamp attached to each
history list event. This time stamp is printed whenever the history
command is executed. This allows the user to keep track of when the
various events occurred. The time stamps are not maintained on the saved
history list (also available in csh); thus, on logging back in, all the
saved history events will be recorded with the login time as their time
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stamp. The time stamp printouts can be omitted from the history list by
adding the -t switch to the history command. Tcsh provides a way to
save, restore and clear the history list in a file.
history -S [<filename>]
history -L [<filename>]
history -c
The 'S' flag saves the current history, the 'L' flags loads the history,
and the 'c' flag clears the history. If a filename is not specified,
then $HOME/.history is used.
14. DIRECTORY ACCESS
Tcsh supports three new flags to control directory style printing for cd,
pushd, popd, and dirs:
-n Print entries in new lines so that the screen width is not exceeded
-l Don't print ~ but print the whole path
-v Print the stack entries one in each line, preceded by the stack
number.
Note that popd +n can be used to pop out stack entries of directories
that do not exist any more.
Tcsh always saves the last directory visited. Changing to the previous
directory can be done by using 'cd -' or 'pushd -'.
Tcsh will now allow the user to access all elements in the directory
stack directly. The syntax "=<digit>" is recognized by tcsh as
indicating a particular directory in the stack. (This works for the
file/command name recognition as well.) This syntax is analogous to the
~ syntax for access to users' home directories. The stack is viewed as
zero-based, i.e., =0 is the same as $cwd, which is the same as ".". As a
special case, the string "=-" is recognized as indicating the last
directory in the stack. Thus,
> dirs -v
0 /usr/net/bin
1 /usr/spool/uucp
2 /usr/accts/sys
> echo =2
/usr/accts/sys
> ls -l =1/LOGFILE
-rw-r--r-- 1 uucp 2594 Jan 19 09:09 /usr/spool/uucp/LOGFILE
> echo =-/.cs*
/usr/accts/sys/.cshrc
> echo =4
Not that many dir stack entries.
>
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Tcsh will complain if you ask for a directory stack item which does not
exist.
In the normal csh, saying "pushd +2" would rotate the entire stack around
through 2 stack elements, placing the entry found there at the top of the
stack. If, however, the new shell variable dextract is set, then issuing
"pushd +n" will cause the nth directory stack element to be extracted
from its current position, which will then be pushed onto the top of the
stack. Example:
> dirs
~ /usr/spool/uucp /usr/net/bin /sys/src
> set dextract
> pushd +2
/usr/net/bin ~ /usr/spool/uucp /sys/src
> unset dextract
> pushd +2
/usr/spool/uucp /sys/src /usr/net/bin ~
Tcsh provides a way to save, restore and clear the directory stack in a
file.
dirs -S [<filename>]
dirs -L [<filename>]
dirs -c
The 'S' flag saves the current directory stack, the 'L' flags loads the
directory stack, and the 'c' flag clears the directory stack. If a
filename is not specified, then $HOME/.cshdirs is used.
In addition, if the shell variable dunique is set, only directories that
are not already in the directory stack will be added when push is
invoked.
The way symbolic links that point to directories are crossed is
determined by the symlinks variable. By default, it is not set to
anything and symbolic links are not treated specially. However, it can be
set to either: chase, ignore, or expand. If symlinks is set to chase,
then every time the directory changes, $cwd reflects the real directory
name, and not the name through the link. A notable exception is the
user's home directory, but that should be fixed. If symlinks is set to
either ignore or expand, then tcsh tries to determine the current
directory name relative to the name of the current directory before the
link was crossed. In simple terms, if you chdir through a symbolic link
and then cd .., you will end .. relatively to where you were before you
crossed the link and not .. relatively to where the symbolic link points.
While ignore affects only builtin commands and completion, expand affects
command execution too, by `fixing' arguments that it considers to be path
names. Unfortunately this does not work in every case, specially when
file arguments are embedded in command line options. Expand also allows
to specify the `real' (as opposed to the one determined relatively to
$cwd), by quoting the file argument.
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For example:
> cd /tmp
> mkdir from from/src to
> ln -s ../from/src to/dst
> unset symlinks
> cd /tmp/to/dst; echo $cwd
/tmp/to/dst
> cd ..; echo $cwd
/tmp/from
> set symlinks=chase
> cd /tmp/to/dst; echo $cwd
/tmp/from/src
> cd ..; echo $cwd
/tmp/from
> set symlinks=ignore
> cd /tmp/to/dst; echo $cwd
/tmp/to/dst
> cd ..; echo $cwd
/tmp/to
> set symlinks=expand
> cd /tmp/to/dst; echo $cwd
/tmp/to/dst
> cd ..; echo $cwd # builtin
/tmp/to
> cd /tmp/to/dst; echo $cwd
/tmp/to/dst
> cd ".."; echo $cwd # quoted
/tmp/from
> /bin/echo .. # rewrites non builtin commands.
/tmp/to
> /bin/echo ".."
While the expand setting is the most convenient, and makes symbolic links
invisible, it can sometimes be misleading and confusing in cases where it
fails to recognize arguments. A compromise is to use the ignore setting
and use the editor functions "normalize-path", bound by default to ^Xn.
15. WATCHING FOR LOGINS AND LOGOUTS
Tcsh has a mechanism so that the user can watch for login and logout
activity of any user or terminal in the system. This is accomplished
using the new special shell variable watch, which contains login/terminal
pattern pairs to be checked for activity. For example:
> set watch=(sys ttyjd root console)
This setting will allow the user to check on when the user "sys" logs in
on /dev/ttyjd. Similarly, it will inform the user of root's activity on
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the console. In order to be more general, the word "any" may be
substituted for either a user's or a terminal's name, thus allowing
> set watch=('b*' any any ttyh0)
which will check for users that match the pattern 'b*' logging in or out
of the system on any terminal, as well as anyone logging in to
/dev/ttyh0. Naturally, the completely general case
> set watch=(any any)
allows the user to check on any and all login/logout activity in the
system.
By default, the interval between checks of users on the system is 10
minutes; this can be changed by making the first element of watch a
number of minutes which should be used instead, as in
> set watch=(40 any any)
which will check for any users logging in or out every 40 minutes.
There is also a new command, log, which is used to cause tcsh to inform
the user of all users/terminals affected by watch whether they have been
announced before or not. This is useful if a user has been on for some
time and cannot remember if a particular person/terminal is online right
now or not. Log will reset all indication of previous announcement and
give the user the login list all over again, as well as printing the
current value of watch.
The first time that watch is set at tcsh startup, all affected users and
terminals will be printed as though those users/terminals had just logged
on. This may appear to be a bug, but is generally considered a feature,
since it allows the user to see who is on when he first logs in.
The format of the printouts can be tailored via setting of the variable
who. In addition to the standard prompt % escapes, the following
sequences are available for the format specification:
%n The name of the user that logged in/out.
%a The observed action, i.e. "logged on",
"logged off", or "replaced <olduser> on".
%l The line (tty) the user is logged on.
%M The full hostname of the remote host ("local"
if non-remote).
%m The hostname up to the first ".". If only
the ip address is available or the utmp
field contains the name of an x-windows
display, the whole name is printed.
The %M and %m sequences are only available on systems that store the
remote hostname in /var/adm/utmp. If who is not set, the format defaults
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to "%n has %a %l from %m.", or "%n has %a %l." on systems that don't
store the hostname.
16. TIMED EVENT LIST
Tcsh now supports a scheduled-event list through the use of the command
sched. This command gives the user a mechanism by which to arrange for
other commands to be executed at given times. An event is added to the
scheduled-event list by saying
> sched [+]hh:mm <command>
as in
> sched 11:00 echo It\'s eleven o\'clock.
This will make an entry in the list at 11am for the echo command to be
run with the given arguments. The time may be specified in either
absolute or relative time, and absolute times may have a
morning/afternoon specification as well, using "am" or "pm." For
example,
> sched +2:15 /usr/lib/uucp/uucico -r1 -sother
> sched 5pm set prompt='[%h] It\'s after 5; go home: >'
> sched +3am echo This syntax doesn\'t work.
Relative time inconsistent with am/pm.
>
Note that tcsh will complain if you try to make faulty time
specifications.
Printing the current time-event list is accomplished by giving the sched
command with no arguments:
> 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: >
>
There is also a mechanism by which the user can remove an item from the
list:
> sched --3
Usage for delete: sched -<item#>.
> sched -3
Not that many scheduled events.
> sched -2
> sched
1 Wed Apr 4 15:42 /usr/lib/uucp/uucico -r1 -sother
>
All commands specified on the scheduled-event list will be executed just
prior to printing the first prompt immediately following the time when
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the command is to be run. Hence, it is possible to miss the exact time
when the command is to be run, but tcsh will definitely get around to all
commands which are overdue at its next prompt. Scheduled-event list
items which come due while tcsh is waiting for user input will be
executed immediately. In no case, however, will normal operation of
already-running commands be interrupted 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 does not
necessarily run a command at exactly the specified time (but only if
another command is already being run). Its major advantage is that
commands which run directly from tcsh, as sched commands are, have access
to shell variables and other structures. This provides a mechanism for
changing one's working environment based on the time of day.
17. BUILTIN FOR ls -F
There is a new builtin command called ls-F which does the same thing as
the command "ls -F". If the shell variable showdots has been set, it
acts like "ls -aF". If showdots is equal to "-A", then ls-F acts like "ls
-AF". Ls-F works like ls, only it is generally faster, since it does not
need to fork and exec, and safer against Trojan horses if the user has
`.' in the execution path. If other switches are passed to ls-F, then the
normal ls is executed. Aliasing ls to ls-F provides a fast alternative
way of listing files. Note that on non BSD machines, where ls -C is not
the default, ls-F, behaves like ls -CF.
ls-F appends the following characters depending on the file type:
= File is an AF_UNIX domain socket.
[if system supports sockets]
| File is a named pipe (fifo)
[if system supports named pipes]
% File is a character device
# File is a block device
/ File is a directory
* File is executable
+ File is a hidden directory [aix]
or context dependent [hpux]
: File is network special [hpux]
On systems that support symbolic links the variable listlinks controls
the way symbolic links are identified. If listlinks is not set then the
character '@' is appended to the file. If listlinks is set then the
following characters are appended to the filename depending on the type
of file the symbolic links points to:
@ File is a symbolic link pointing
to a non-directory
> File is a symbolic link pointing
to a directory
& File is a symbolic link pointing
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to nowhere
While setting listlinks can be helpful while navigating around the file
system, it slows down ls-F and it causes mounting of file systems if the
symbolic links point to an NFS auto-mounted partition.
18. GLOBBING SYNTAX ADDITIONS
The syntax for any character in a range (for example ".[a-z]*") has been
extended so as to conform with standard Unix regular expression syntax
(see ed(1)). Specifically, after an open bracket ("["), if the first
character is a caret ("^") then the character matched will be any not in
the range specified. For example:
> cd ~
> echo .[a-z]*
.cshrc .emacs .login .logout .menuwmrc
> echo .[^.]*
.Xdefaults .Xinit .cshrc .emacs .login .logout .menuwmrc
>
Note that the second form includes .Xdefaults and .Xinit because 'X' (and
all the lower case letters) are outside of the range of a single '.'.
Also the ability to negate a globbing pattern has been added:
> echo *
foo foobar bar barfoo
> echo ^foo*
bar barfoo
Note that this does not work correctly if the expression does not have
any wildcard characters (?*[]) or if the expression has braces {}.
Currently, \< and \> are not supported.
19. NEW ENVIRONMENT AND SHELL VARIABLES
On startup, tcsh now automatically initializes the environment variable
HOST to the name of the machine that it is running on. It does this by
doing a gethostname(2) system call, and setting HOST to the result.
Tcsh also initializes the environment variable HOSTTYPE to a symbolic
name for the type of computer that it is running on. This is useful when
sharing a single physical directory between several types of machines
(running NFS, for instance). For example, if the following is in .login:
set path = (~/bin.$HOSTTYPE /usr/ucb /bin /usr/bin /usr/games .)
and the user has directories named "bin.machine" (where machine is a name
from the list below), then the user can have the same programs compiled
for different machines in the appropriate "bin.machine" directories and
tcsh will run the binary for the correct machine.
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The current possible values are:
386BSD an Intel 386, running 386BSD
aix370 an IBM 370, running aix
aixESA an IBM ESA, running aix
alliant an Alliant FX series
alliant-fx80 an Alliant FX80 (mc68000 based)
alliant-fx2800 an Alliant FX2800 (i860 based)
alpha an DEC Alpha running OSF/1
amdahl an Amdahl running uts 2.1
amiga an amiga running amix 2.02
apollo an Apollo running DomainOS
att3b15 an AT&T 3b15
att3b2 an AT&T 3b2
att3b20 an AT&T 3b20
att3b5 an AT&T 3b5
balance a Sequent Balance (32000 based)
bsd386 an Intel 386, running BSDI's bsd386
butterfly a BBN Computer Butterfly 1000
coh386 a 386 running Coherent 4.0
coherent an unknown machine running Coherent
convex a Convex
cray a Cray running Unicos
decstation a DecStation XXXX
eta10 an ETA 10 running SVR3
gould-np1 a Gould NP1
hk68 a Heurikon HK68 runn
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