An Introduction to the Z Shell
pfalstad@phoenix.princeton.edu
zsh is a shell designed for interactive use, although it is
also a powerful scripting language. Many of the useful
features of bash, ksh, and tcsh were incorporated into zsh;
many original features were added. This document details
some of the unique features of zsh. It assumes basic
knowledge of the standard UNIX shells; the intent is to show
a reader already familiar with one of the other major shells
what makes zsh more useful or more powerful. This document
is not at all comprehensive; read the manual entry for a
description of the shell that is complete and concise,
although somewhat overwhelming and devoid of examples.
Otherwise known as globbing, filename generation is quite
extensive in zsh. Of course, it has all the basics:
Makefile file.pro foo.o main.o q.c run234 stuff
bar.o foo link morestuff run123 run240 sub
file.h foo.c main.h pipe run2 run303
bar.o foo.c foo.o main.o q.c
bar.o file.h foo.o main.h main.o
Also, if the EXTENDEDGLOB option is set, some new features
are activated. For example, the ^ character negates the
Makefile file.pro link morestuff run2 run303
bar.o foo main.h pipe run234 stuff
file.h foo.o main.o run123 run240 sub
Makefile link pipe run2 run240 stuff
foo morestuff run123 run234 run303 sub
bar.o foo link morestuff run123 run240 sub
file.h foo.c main.h pipe run2 run303
file.pro foo.o main.o q.c run234 stuff
.rhosts bar.o file.h file.pro foo.o main.h main.o
An expression of the form <x-y> matches a range of integers:
run123 run2 run234 run240 run303
bar.o file.pro foo.c foo.o main.o q.c
Also, the string ****/ forces a recursive search of sub-
Makefile file.pro foo.o main.o q.c run234 stuff
bar.o foo link morestuff run123 run240 sub
file.h foo.c main.h pipe run2 run303
stuff/xxx/foobar stuff/yyy/frobar
file.h foo foo.o stuff/xxx/foobar
file.pro foo.c stuff/file stuff/yyy/frobar
bar.o stuff/xxx/foobar stuff/yyy/frobar
stuff/xxx/foobar stuff/yyy/frobar
It is possible to exclude certain files from the patterns
using the ~ character. A pattern of the form *.c~bar.c
lists all files matching *.c, except for the file bar.c.
One can add a number of qualifiers to the end of any of
these patterns, to restrict matches to certain file types.
A qualified pattern is of the form
with single-letter qualifiers inside the parentheses.
Makefile foo* main.h q.c run240
bar.o foo.c main.o run123 run303
file.h foo.o morestuff/ run2 stuff/
file.pro link@ pipe run234 sub
foo* link@ morestuff/ stuff/
foo* link@ morestuff/ stuff/
foo* link@ morestuff/ stuff/
bar.o foo* link@ morestuff/ run123 run240
file.h foo.c main.h pipe run2 run303
file.pro foo.o main.o q.c run234 stuff/
Note that *(x) and *(*) both match executables. *(X)
matches files executable by others, as opposed to *(x),
which matches files executable by the owner. *(R) and *(r)
match readable files; *(W) and *(w), which checks for writ-
able files. *(W) is especially important, since it checks
for world-writable files:
bar.o foo* link@ morestuff/ run123 run240
file.h foo.c main.h pipe run2 run303
file.pro foo.o main.o q.c run234 stuff/
lrwxrwxrwx 1 pfalstad 10 May 23 18:12 link -> /bin/false*
-rw-rw-rw- 1 pfalstad 0 May 23 18:12 run240
You can filter out the symbolic links with the ^ character:
foo* link@ morestuff/ stuff/
To find all plain files, you can use .:
Makefile file.h foo* foo.o main.o run123 run234 run303
bar.o file.pro foo.c main.h q.c run2 run240 sub
link@ morestuff/ pipe stuff/
prw-r--r-- 1 pfalstad 0 May 23 18:12 pipe
*(U) matches all files owned by you. To search for all
files not owned by you, use *(^U):
-rw------- 1 subbarao 29 May 23 18:13 sub
This searches for setuid files:
-rwsr-xr-x 1 pfalstad 16 May 23 18:12 foo*
This checks for a certain user's files:
% ypmatch subbarao passwd
subbarao:*:3338:35:Kartik Subbarao:/u/subbarao:/usr/princeton/bin/zsh
-rw------- 1 subbarao 29 May 23 18:13 sub
There are five startup files that zsh will read commands
If ZDOTDIR is not set, then the value of HOME is used; this
.zshenv is sourced on all invocations of the shell, unless
the -f option is set. It should contain commands to set the
command search path, plus other important environment vari-
ables. .zshenv should not contain commands that produce
output or assume the shell is attached to a tty.
.zshrc is sourced in interactive shells. It should contain
commands to set up aliases, functions, options, key bind-
.zlogin is sourced in login shells. It should contain com-
mands that should be executed only in login shells. .zlo-
gout is sourced when login shells exit. .zprofile is simi-
lar to .zlogin, except that it is sourced before .zshrc.
.zprofile is meant as an alternative to .zlogin for ksh
fans; the two are not intended to be used together, although
this could certainly be done if desired. .zlogin is not the
place for alias definitions, options, environment variable
settings, etc.; as a general rule, it should not change the
shell environment at all. Rather, it should be used to set
the terminal type and run a series of external commands
zsh also allows you to create your own commands by defining
shell functions. For example:
> ypmatch $1 passwd.byname
pfalstad:*:3564:35:Paul John Falstad:/u/pfalstad:/usr/princeton/bin/zsh
This function looks up a user in the NIS password map. The
$1 expands to the first argument to yp. The function could
have been equivalently defined in one of the following ways:
> ypmatch $1 passwd.byname
> ypmatch $1 passwd.byname
% function yp () ypmatch $1 passwd.byname
Note that aliases are expanded when the function definition
is parsed, not when the function is executed. For example:
pfalstad:*:3564:35:Paul John Falstad:/u/pfalstad:/usr/princeton/bin/zsh
Since the alias was defined after the function was parsed,
it has no effect on the function's execution. However, if
we define the function again with the alias in place:
% function yp () { ypmatch $1 passwd.byname }
it is parsed with the new alias definition in place. There-
fore, in general you must define aliases before functions.
We can make the function take multiple arguments:
> do ypmatch $i passwd.byname
% yp pfalstad subbarao sukthnkr
pfalstad:*:3564:35:Paul John Falstad:/u/pfalstad:/usr/princeton/bin/zsh
subbarao:*:3338:35:Kartik Subbarao:/u/subbarao:/usr/princeton/bin/zsh
sukthnkr:*:1267:35:Rahul Sukthankar:/u/sukthnkr:/usr/princeton/bin/tcsh
The for i loops through each of the function's arguments,
setting i equal to each of them in turn. We can also make
the function do something sensible if no arguments are
> then echo usage: yp name ...; fi
> for i; do ypmatch $i passwd.byname; done
pfalstad:*:3564:35:Paul John Falstad:/u/pfalstad:/usr/princeton/bin/zsh
sukthnkr:*:1267:35:Rahul Sukthankar:/u/sukthnkr:/usr/princeton/bin/tcsh
$# is the number of arguments supplied to the function. If
it is equal to zero, we print a usage message; otherwise, we
loop through the arguments, and ypmatch all of them.
Here's a function that selects a random line from a file:
> sed -n $[RANDOM % z + 1]p $1
PHOENIX WILL BE DOWN briefly Friday morning, 5/24/91 from 8 AM to
SunOS Release 4.1.1 (PHOENIX) #19: Tue May 14 19:03:15 EDT 1991
| Please use the "msgs" command to read announcements. Refer to the |
randline has a local variable, z, that holds the number of
lines in the file. $[RANDOM % z + 1] expands to a random
number between 1 and z. An expression of the form $[...]
expands to the value of the arithmetic expression within the
brackets, and the RANDOM variable returns a random number
each time it is referenced. % is the modulus operator, as
in C. Therefore, sed -n $[RANDOM%z+1]p picks a random line
from its input, from 1 to z.
Function definitions can be viewed with the functions buil-
sed -n $[RANDOM % z + 1]p $1
sed -n $[RANDOM % z + 1]p $1
-rw-r--r-- 1 pfalstad 29 May 24 04:38 bar
-rw-r--r-- 1 pfalstad 29 May 24 04:38 foo
-rwxr-xr-x 1 pfalstad 29 May 24 04:38 bar
-rwxr-xr-x 1 pfalstad 29 May 24 04:38 foo
Note that this could also have been implemented as an alias:
-rwxr-xr-x 1 pfalstad 29 May 24 04:38 bar
-rwxr-xr-x 1 pfalstad 29 May 24 04:38 foo
Instead of defining a lot of functions in your .zshrc, all
of which you may not use, it is often better to use the
autoload builtin. The idea is, you create a directory where
function definitions are stored, declare the names in your
.zshrc, and tell the shell where to look for them. Whenever
you reference a function, the shell will automatically load
% chmod 755 /tmp/funs/{cx,yp}
egsirer:*:3214:35:Emin Gun Sirer:/u/egsirer:/bin/sh
This idea has other benefits. By adding a #! header to the
files, you can make them double as shell scripts. (Although
it is faster to use them as functions, since a separate pro-
sukthnkr:*:1267:35:Rahul Sukthankar:/u/sukthnkr:/usr/princeton/bin/tcsh
Now other people, who may not use zsh, or who don't want to
copy all of your .zshrc, may use these functions as shell
One nice feature of zsh is the way it prints directories.
For example, if we set the prompt like this:
the shell will print the current directory in the prompt,
using the ~ character. However, zsh is smarter than most
other shells in this respect:
~maruchck/lib/fun> foo=/usr/princeton/common/src
~maruchck/lib/fun> cd ~foo
/usr/princeton/common> cd src
Note that zsh prints other users' directories in the form
~user. Also note that you can set a parameter and use it as
a directory name; zsh will act as if foo is a user with the
login directory /usr/princeton/common/src. This is con-
venient, especially if you're sick of seeing prompts like
phoenix:/usr/princeton/common/src/X.V11R4/contrib/clients/xv/docs>
If you get stuck in this position, you can give the current
directory a short name, like this:
/usr/princeton/common/src/news/nntp/inews> inews=$PWD
/usr/princeton/common/src/news/nntp/inews> echo ~inews
/usr/princeton/common/src/news/nntp/inews
When you reference a directory in the form ~inews, the shell
assumes that you want the directory displayed in this form;
thus simply typing echo ~inews or cd ~inews causes the
prompt to be shortened. You can define a shell function for
~inews> namedir () { $1=$PWD ; : ~$1 }
~inews> cd /usr/princeton/bin
/usr/princeton/bin> namedir pbin
~pbin> cd /var/spool/mail
/var/spool/mail> namedir spool
You may want to add this one-line function to your .zshrc.
zsh can also put the current directory in your title bar, if
you are using a windowing system. One way to do this is
with the chpwd function, which is automatically executed by
the shell whenever you change directory. If you are using
chpwd () { print -Pn '^[]2;%~^G' }
The -P option tells print to treat its arguments like a
prompt string; otherwise the %~ would not be expanded. The
-n option suppresses the terminating newline, as with echo.
If you are using an IRIS wsh, do this:
chpwd () { print -Pn '^[P1.y%~^[' }
The print -D command has other uses. For example, to print
the current directory to standard output in short form, you
and to print each component of the path in short form:
/bin /usr/bin ~locbin ~locbin/X11 ~/bin
If you use csh, you may know about directory stacks. The
pushd command puts the current directory on the stack, and
changes to a new directory; the popd command pops a direc-
tory off the stack and changes to it.
Z /usr/etc> pushd /usr/bin
zsh's directory stack commands work similarly. One differ-
ence is the way pushd is handled if no arguments are given.
As in csh, this exchanges the top two elements of the direc-
unless the stack only has one entry:
or unless the PUSHDTOHOME option is set:
As an alternative to using directory stacks in this manner,
we can get something like a directory history by setting a
few more options and parameters:
~> setopt autopushd pushdminus pushdsilent pushdtohome
Note that =2 expanded to the second directory in the history
list, and that cd -3 recalled the third directory in the
You may be wondering what all those options do. AUTOPUSHD
made cd act like pushd. (alias cd=pushd is not sufficient,
for various reasons.) PUSHDMINUS swapped the meaning of cd
+1 and cd -1; we want them to mean the opposite of what they
mean in csh, because it makes more sense in this scheme, and
PUSHDSILENT keeps the shell from printing the directory
stack each time we do a cd, and PUSHDTOHOME we mentioned
/usr/pub> unsetopt pushdsilent
/etc /usr/pub /tmp ~ /usr/bin /usr
~ /etc /usr/pub /tmp ~ /usr/bin /usr
/etc ~ /usr/pub /tmp ~ /usr/bin /usr
DIRSTACKSIZE keeps the directory stack from getting too
large, much like HISTSIZE:
Command/Process Substitution
Command substitution in zsh can take two forms. In the
traditional form, a command enclosed in backquotes (`...`)
is replaced on the command line with its output. This is
the form used by the older shells. Newer shells (like zsh)
also provide another form, $(...). This form is much easier
-rwxr-xr-x 1 root 1209702 May 14 19:04 /vmunix
-rwxr-xr-x 1 root 1209702 May 14 19:04 /vmunix
subbarao ttyt7 May 23 15:02 (mad55sx15.Prince)
pfalstad ttyu1 May 23 16:25 (mad55sx14.Prince)
subbarao ttyu6 May 23 15:04 (mad55sx15.Prince)
pfalstad ttyv3 May 23 16:25 (mad55sx14.Prince)
% who | grep mad | awk '{print $2}'
crwx-w---- 1 subbarao 20, 71 May 23 18:35 ttyt7
crw--w---- 1 pfalstad 20, 81 May 23 18:42 ttyu1
crwx-w---- 1 subbarao 20, 86 May 23 18:38 ttyu6
crw--w---- 1 pfalstad 20, 99 May 23 18:41 ttyv3
Many common uses of command substitution, however, are
superseded by other mechanisms of zsh:
crw-rw-rw- 1 root 20, 28 May 23 18:35 /dev/ttyqc
crw-rw-rw- 1 root 20, 28 May 23 18:35 /dev/ttyqc
-rwxr-xr-x 1 root 172032 Mar 6 18:40 /usr/princeton/bin/rn
-rwxr-xr-x 1 root 172032 Mar 6 18:40 /usr/princeton/bin/rn
A command name with a = prepended is replaced with its full
pathname. This can be very convenient. If it's not con-
venient for you, you can turn it off:
Another nice feature is process substitution:
% who | fgrep -f =(print -l root lemke shgchan subbarao)
root console May 19 10:41
lemke ttyq0 May 22 10:05 (narnia:0.0)
lemke ttyr7 May 22 10:05 (narnia:0.0)
lemke ttyrd May 22 10:05 (narnia:0.0)
shgchan ttys1 May 23 16:52 (gaudi.Princeton.)
subbarao ttyt7 May 23 15:02 (mad55sx15.Prince)
subbarao ttyu6 May 23 15:04 (mad55sx15.Prince)
shgchan ttyvb May 23 16:51 (gaudi.Princeton.)
A command of the form =(...) is replaced with the name of a
file containing its output. (A command substitution, on the
other hand, is replaced with the output itself.) print -l is
like echo, excepts that it prints its arguments one per
line, the way fgrep expects them:
We could also have written:
% who | fgrep -f =(echo 'root
Using process substitution, you can edit the output of a
% ed =(who | fgrep -f ~/.friends)
root console May 19 10:41
shgchan ttys1 May 23 16:52 (gaudi.Princeton.)
subbarao ttyt7 May 23 15:02 (mad55sx15.Prince)
subbarao ttyu6 May 23 15:04 (mad55sx15.Prince)
shgchan ttyvb May 23 16:51 (gaudi.Princeton.)
or easily read archived mail:
% mail -f =(zcat ~/mail/oldzshmail.Z)
"/tmp/zsha06024": 84 messages, 0 new, 43 unread
> 1 U TO: pfalstad, zsh (10)
2 U nytim!tim@uunet.uu.net, Re: Zsh on Sparc1 /SunOS 4.0.3
3 U JAM%TPN@utrcgw.utc.com, zsh fix (15)
4 U djm@eng.umd.edu, way to find out if running zsh? (25)
5 U djm@eng.umd.edu, Re: way to find out if running zsh? (17)
6 r djm@eng.umd.edu, Meta . (18)
7 U jack@cs.glasgow.ac.uk, Re: problem building zsh (147)
8 U nytim!tim@uunet.uu.net, Re: Zsh on Sparc1 /SunOS 4.0.3
9 ursa!jmd, Another fix... (61)
10 U pplacewa@bbn.com, Re: v18i084: Zsh 2.00 - A small complaint (36)
11 U lubkin@cs.rochester.edu, POSIX job control (34)
12 U yale!bronson!tan@uunet.UU.NET
13 U brett@rpi.edu, zsh (36)
14 S subbarao, zsh sucks!!!! (286)
15 U snibru!d241s008!d241s013!ala@relay.EU.net, zsh (165)
16 U nytim!tim@uunet.UU.NET, Re: Zsh on Sparc1 /SunOS 4.0.3
17 U subbarao, zsh is a junk shell (43)
18 U amaranth@vela.acs.oakland.edu, zsh (33)
Note that the shell creates a temporary file, and deletes it
when the command is finished.
If you read zsh's man page, you may notice that <(...) is
another form of process substitution which is similar to
=(...). There is an important difference between the two.
In the <(...) case, the shell creates a named pipe (FIFO)
instead of a file. This is better, since it does not fill
up the file system; but it does not work in all cases. In
fact, if we had replaced =(...) with <(...) in the examples
above, all of them would have stopped working except for
fgrep -f <(...). You can not edit a pipe, or open it as a
mail folder; fgrep, however, has no problem with reading a
list of words from a pipe. You may wonder why diff <(foo)
bar doesn't work, since foo | diff - bar works; this is
because diff creates a temporary file if it notices that one
of its arguments is -, and then copies its standard input to
Often-used commands can be abbreviated with an alias:
or commands with certain desired options:
Login name: root In real life: Operator
Directory: / Shell: /bin/csh
On since May 19 10:41:15 on console 3 days 5 hours Idle Time
% alias lock='lock -p -60000'
lock: /dev/ttyr4 on phoenix. timeout in 60000 minutes
time now is Fri May 24 04:23:18 EDT 1991
Aliases can also be used to replace old commands:
% alias grep=egrep ps=sps make=gmake
% alias whoami='echo root'
% alias sz='ls -l | sort -n +3 | tail -10'
drwxr-sr-x 7 bin 3072 May 23 11:59 etc
drwxrwxrwx 26 root 5120 May 24 04:20 tmp
drwxr-xr-x 2 root 8192 Dec 26 19:34 lost+found
drwxr-sr-x 2 bin 14848 May 23 18:48 dev
-r--r--r-- 1 root 140520 Dec 26 20:08 boot
-rwxr-xr-x 1 root 311172 Dec 26 20:08 kadb
-rwxr-xr-x 1 root 1209695 Apr 16 15:33 vmunix.old
-rwxr-xr-x 1 root 1209702 May 14 19:04 vmunix
-rwxr-xr-x 1 root 1209758 May 21 12:23 vmunix.new.kernelmap.old
-rwxr-xr-x 1 root 1711848 Dec 26 20:08 vmunix.org
% alias rable='ls -AFtrd *(R)' nrable='ls -AFtrd *(^R)'
README func/ bin/ pub/ News/ src/
nicecolors etc/ scr/ tmp/ iris/ zsh*
(The pattern *(R) matches all readable files in the current
directory, and *(^R) matches all unreadable files.)
Most other shells have aliases of this kind (command
aliases). However, zsh also has global aliases, which are
substituted anywhere on a line. Global aliases can be used
to abbreviate frequently-typed usernames, hostnames, etc.
% alias -g me=pfalstad gun=egsirer mjm=maruchck
pfalstad ttyp0 May 24 03:39 (mickey.Princeton)
pfalstad ttyp5 May 24 03:42 (mickey.Princeton)
Login name: egsirer In real life: Emin Gun Sirer
Directory: /u/egsirer Shell: /bin/sh
Last login Thu May 23 19:05 on ttyq3 from bow.Princeton.ED
New mail received Fri May 24 02:30:28 1991;
unread since Fri May 24 02:30:27 1991
% alias -g phx=phoenix.princeton.edu warc=wuarchive.wustl.edu
Connected to wuarchive.wustl.edu.
Here are some more interesting uses.
% alias -g M='| more' GF='| fgrep -f ~/.friends'
% who M # pipes the output of who through more
% who GF # see if your friends are on
% w GF # see what your friends are doing
Another example makes use of zsh's process substitution. If
you run NIS, and you miss being able to do this:
% grep pfalstad /etc/passwd
you can define an alias that will seem more natural than
% alias -g PASS='<(ypcat passwd)'
pfalstad:*:3564:35:Paul John Falstad:/u/pfalstad:/usr/princeton/bin/zsh
If you're really crazy, you can even call it /etc/passwd:
% alias -g /etc/passwd='<(ypcat passwd)'
% grep pfalstad /etc/passwd
pfalstad:*:3564:35:Paul John Falstad:/u/pfalstad:/usr/princeton/bin/zsh
The last example shows one of the perils of global aliases;
they have a lot of potential to cause confusion. For exam-
ple, if you defined a global alias called | (which is possi-
ble), zsh would begin to act very strangely; every pipe sym-
bol would be replaced with the text of your alias. To some
extent, global aliases are like macros in C; discretion is
advised in using them and in choosing names for them. Using
names in all caps is not a bad idea, especially for aliases
which introduce shell metasyntax (like M and GF above).
Note that zsh aliases are not like csh aliases. The syntax
for defining them is different, and they do not have argu-
ments. All your favorite csh aliases will probably not work
under zsh. For example, if you try:
alias rm mv '\!* /tmp/wastebasket'
no aliases will be defined, but zsh will not report an
error. In csh, this line defines an alias that makes rm
safe---files that are rm'd will be moved to a temporary
directory instead of instantly destroyed. In zsh's syntax,
however, this line asks the shell to print any existing
alias definitions for rm, mv, or !* /tmp/wastebasket. Since
there are none, most likely, the shell will not print any-
thing, although alias will return a nonzero exit code. The
alias rm='mv \!* /tmp/wastebasket'
However, this won't work either:
zsh: no matches found: !*
While this makes rm safe, it is certainly not what the user
intended. In zsh, you must use a shell function for this:
% rm () { mv $* /tmp/wastebasket }
While this is much cleaner and easier to read (I hope you
will agree), it is not csh-compatible. Therefore, a script
to convert csh aliases and variables has been provided. You
should only need to use it once, to convert all your csh
aliases and parameters to zsh format:
on last -2 !:1 ; who | grep !:1
on () { last -2 $1 ; who | grep $1 }
The first two aliases were converted to regular zsh aliases,
while the third, since it needed to handle arguments, was
converted to a function. c2z can convert most aliases to
zsh format without any problems. However, if you're using
some really arcane csh tricks, or if you have an alias with
a name like do (which is reserved in zsh), you may have to
fix some of the aliases by hand.
The c2z script checks your csh setup, and produces a list of
zsh commands which replicate your aliases and parameter set-
tings as closely as possible. You could include its output
in your startup file, .zshrc.
There are several ways to manipulate history in zsh. One
way is to use csh-style ! history:
% /usr/local/bin/!:0 !-2*:s/foo/bar/ >>!$
If you don't want to use this, you can turn it off by typing
Another way is to use the fc command. For example, if you
type an erroneous command:
% for i in `cat /etc/clients`
zsh: command not found: rpu
zsh: command not found: rpu
zsh: command not found: rpu
typing fc will execute an editor on this command, allowing
you to fix it. (The default editor is vi, by the way, not
for i in `cat /etc/clients`
beam up 2 days, 10:17, load average: 0.86, 0.80, 0.50
bow up 4 days, 8:41, load average: 0.91, 0.80, 0.50
burn up 17:18, load average: 0.91, 0.80, 0.50
burst up 9 days, 1:49, load average: 0.95, 0.80, 0.50
tan up 11:14, load average: 0.91, 0.80, 0.50
bathe up 3 days, 17:49, load average: 1.84, 1.79, 1.50
bird up 1 day, 9:13, load average: 1.95, 1.82, 1.51
bonnet up 2 days, 21:18, load average: 0.93, 0.80, 0.50
A variant of the fc command is r, which redoes the last com-
mand, with optional changes:
zsh's command line editor, ZLE, is quite powerful. It is
designed to emulate either emacs or vi; the default is
emacs. To set the bindings for vi mode, type bindkey -v.
In addition to basic editing, the shell allows you to recall
previous lines in the history. In emacs mode, this is done
- README file mail pub tmp
Mailboxes bin func nicecolors scr zsh
Pressing ^P once brings up the previous line (echo foobar);
pressing it again brings up the line before that (ls ~).
The cursor is left at the end of the line, allowing you to
edit the line if desired before executing it. In many
cases, ZLE eliminates the need for the fc command, since it
is powerful enough to handle even multiline commands:
Now you can just move up to the part you want to change...
change it, and execute the new command.
Also, you can search the history for a certain command using
Another way is to do an incremental search, emacs-style:
Another useful feature of the editor is command and filename
If the completion is ambiguous, the editor will beep. You
can list possible completions by pressing ^D:
vmunix.new.kernelmap.old vmunix.org
Or, you could just set the AUTOLIST option:
vmunix.new.kernelmap.old vmunix.org
Another option you could set is RECEXACT, which causes exact
matches to be accepted, even if there are other possible
vmunix.new.kernelmap.old vmunix.org
The fignore variable lists suffixes of files to ignore
% fignore=( .o \~ .bak .junk )
Since foofile.o has a suffix that is in the fignore list, it
was not considered a possible completion of foo.
Username completion is also supported:
and parameter name completion:
and hostname completion, if you give the shell a list of
% hosts=( phoenix.princeton.edu uunet.uu.net nic.ddn.mil
> diskfarm.princeton.edu gnu.ai.mit.edu
% telnet diskfarm.princeton.edu _
% mail subbarao@phoenix.princeton.edu _
% bindkey '^X^X' push-line _
The compctl command is used to control how completion works.
For example, to specify that certain commands show take com-
mands as arguments, you use compctl -c:
To specify that a command should complete filenames, you
should use compctl -f. This is the default. It can be com-
Similarly, use -h to specify hostnames, -o to specify
options, -v to specify variables, and -b to specify bind-
You can also use -k to specify a custom list of keywords to
% ftphosts=(ftp.uu.net wuarchive.wustl.edu)
% compctl -k ftphosts ftp
% ftp wuarchive.wustl.edu _
% friends=(cpirazzi subbarao sukthnkr)
% compctl -k friends mail finger su
In addition to completion, TAB performs expansion if possi-
% ls foofile.c fortune.c rnd.c strfile.c unstr.c_
For example, suppose you have a bunch of weird files in an
* * * ; & % $??foo dspfok foo.c
You want to remove them, but you don't want to damage foo.c.
Here is one way to do this:
% rm \ \ \*\ \*\ \*\ \ \ \!\"foo\"\! \;\ \&\ %\ \$'
'foo \`\ \\\ \` dspfok foo foo.c rrr_
When you expand *, zsh inserts the names of all the files
into the editing buffer, with proper shell quoting. Now,
just move back and remove foo.c from the buffer:
% rm \ \ \*\ \*\ \*\ \ \ \!\"foo\"\! \;\ \&\ %\ \$'
'foo \`\ \\\ \` dspfok foo _rr
and press return. Everything except foo.c will be deleted
Here's another trick; let's say you have typed this command
% gcc -o x.out foob.c -g -Wpointer-arith -Wtrigraphs_
and you forget which library you want. You need to escape
out for a minute and check by typing ls /usr/lib, or some
other such command; but you don't want to retype the whole
command again, and you can't press return now because the
current command is incomplete. In zsh, you can put the line
on the buffer stack, using ESC-Q, and type some other com-
mands. The next time a prompt is printed, the gcc line will
be popped off the stack and put in the editing buffer
automatically; you can then enter the proper library name
and press return (or, ESC-Q again and look for some other
libraries whose names you forgot).
A similar situation: what if you forget the option to gcc
that finds bugs using AI techniques? You could either use
ESC-Q again, and type man gcc, or you could press ESC-H,
which essentially does the same thing; it puts the current
line on the buffer stack, and executes the command run-help
gcc, where run-help is an alias for man.
Another interesting command is ESC-A. This executes the
current line, but retains it in the buffer, so that it
appears again when the next prompt is printed. Also, the
cursor stays in the same place. This is useful for execut-
ing a series of similar commands:
% cc grok.c -g -lc -lgl -lsun -lmalloc -Bstatic -o b.out
% cc fubar.c -g -lc -lgl -lsun -lmalloc -Bstatic -o b.out
% cc fooble.c -g -lc -lgl -lsun -lmalloc -Bstatic -o b.out
The ESC-' command is useful for managing the shell's quoting
conventions. Let's say you want to print this string:
don't do that; type 'rm -rf \*', with a \ before the *.
All that is necessary is to type it into the editing buffer:
% don't do that; type 'rm -rf \*', with a \ before the *.
press ESC-' (escape-quote):
% 'don'\''t do that; type '\''rm -rf \*'\'', with a \ before the *.'
then move to the beginning and add the echo command.
% echo 'don'\''t do that; type '\''rm -rf \*'\'', with a \ before the *.'
don't do that; type 'rm -rf \*', with a \ before the *.
Let's say you want to create an alias to do this echo com-
mand. This can be done by recalling the line with ^P and
% 'echo '\''don'\''\'\'''\''t do that; type '\''\'\'''\''rm -rf
\*'\''\'\'''\'', with a \ before the *.'\'''
and then move to the beginning and add the command to create
% alias zoof='echo '\''don'\''\'\'''\''t do that; type '\''\'\'''\''rm
-rf \*'\''\'\'''\'', with a \ before the *.'\'''
don't do that; type 'rm -rf \*', with a \ before the *.
Another interesting option is MENUCOMPLETE. This affects
the way TAB works. Let's look at the /vmunix example again:
% ls /vmunix.new.kernelmap.oldTAB
Each time you press TAB, it displays the next possible com-
pletion. In this way, you can cycle through the possible
completions until you find the one you want.
The AUTOMENU option makes a nice compromise between this
method of completion and the regular method. If you set
this option, pressing the TAB key repeatedly after an ambi-
guous completion will cycle through the possible comple-
Each of the above editor commands was actually a function
bound by default to a certain key. The real names of the
These bindings are arbitrary; you could change them if you
want. For example, to bind accept-line to ^Z:
% bindkey '^Z' accept-line
Another idea would be to bind the delete key to delete-char;
this might be convenient if you use ^H for backspace.
% bindkey '^?' delete-char
Or, you could bind ^X^H to run-help:
% bindkey '^X^H' run-help
% bindkey '^X^Z' universal-argument
% bindkey ' ' magic-space
% bindkey -s '^T' 'uptime
universal-argument multiplies the next command by 4. Thus
^X^Z^W might delete the last four words on the line. If you
bind space to magic-space, then csh-style history expansion
is done on the line whenever you press the space bar.
The -s flag to bindkey specifies that you are binding the
key to a string, not a command. Thus bindkey -s '^T'
'uptime\n' lets you VMS lovers get the load average whenever
If you have a NeXT keyboard, the one with the | and \ keys
very inconveniently placed, the following bindings may come
Now you can type ALT-/ to get a backslash, and ALT-= to get
a vertical bar. This only works inside zsh, of course;
bindkey has no effect on the key mappings inside talk or
Another use of the editor is to edit the value of variables.
For example, an easy way to change your path is to use the
> /u/pfalstad/scr:/u/pfalstad/bin/sun4:/u/maruchck/scr:/u/subbarao/bin:/u/maruc
hck/bin:/u/subbarao/scripts:/usr/princeton/bin:/usr/ucb:/usr/bin:/bin:/usr/host
s:/usr/princeton/bin/X11:/./usr/lang:/./usr/etc:/./etc
You can now edit the path. When you press return, the con-
tents of the edit buffer will be assigned to PATH.
In zsh, parameters are set like this:
Spaces before or after the = are frowned upon:
zsh: command not found: foo
Also, set doesn't work for setting parameters:
Note that no error message was printed. This is because
both of these commands were perfectly valid; the set builtin
assigns its arguments to the positional parameters ($1, $2,
If you're really intent on using the csh syntax, define a
But then, of course you can't use the form of set with
options, like set -F (which turns off filename generation).
Also, the set command by itself won't list all the parame-
ters like it should. To get around that you need a case
> -*|+*|'') builtin set $* ;;
For the most part, this should make csh users happy.
The following sh-style operators are supported in zsh:
Also, csh-style : modifiers may be appended to a parameter
/home/learning/pf/zsh/zsh2.00/src
/home/learning/pf/zsh/zsh2.00
The equivalent constructs in ksh (which are also supported
in zsh) are a bit more general and easier to remember. When
the shell expands ${foo#pat}, it checks to see if pat
matches a substring at the beginning of the value of foo.
If so, it removes that portion of foo, using the shortest
possible match. With ${foo##pat}, the longest possible
match is removed. ${foo%pat} and ${foo%%pat} remove the
match from the end. Here are the ksh equivalents of the :
/home/learning/pf/zsh/zsh2.00
zsh also has upper/lowercase modifiers:
and a substitution modifier:
foo.c foo.h foo.o foo.pro
% for i in foo.*; mv $i $i:s/foo/bar/
bar.c bar.h bar.o bar.pro
One possible source of confusion is the fact that in zsh,
the result of parameter substitution is not split into
words. Thus, this will not work:
% srcs='glob.c exec.c init.c'
glob.c exec.c init.c not found
This is considered a feature, not a bug. If splitting were
done by default, as it is in most other shells, functions
like this would not work properly:
Of course, a hackish workaround is available in sh (and
If you like the sh behaviour, zsh can accomodate you:
Another way to get the $srcs trick to work is to use an
% srcs=( glob.c exec.c init.c )
% alias -g SRCS='exec.c glob.c init.c'
Another option that modifies parameter expansion is RCEX-
foo/glob.c foo/exec.c foo/init.c
foo/glob.c foo/exec.c foo/init.c
foo/glob.c foo/exec.c foo/init.c
The shell has many predefined parameters that may be
accessed. Here are some examples:
($? and $status are equivalent.)
~+ and ~- are short for $PWD and $OLDPWD, respectively.
The cdpath variable sets the search path for the cd command.
If you do not specify . somewhere in the path, it is assumed
to be the first component.
% cdpath=( /usr ~ ~/zsh )
5bin dict lang net sccs sys
5include etc lector nserve services tmp
5lib export lib oed share ucb
adm games local old skel ucbinclude
bin geac lost+found openwin spool ucblib
boot hosts macsyma_417 pat src xpg2bin
demo include man princeton stand xpg2include
diag kvm mdec pub swap xpg2lib
PATH and path both set the search path for commands. These
two variables are equivalent, except that one is a string
and one is an array. If the user modifies PATH, the shell
changes path as well, and vice versa.
% PATH=/bin:/usr/bin:/tmp:.
% path=( /usr/bin . /usr/local/bin /usr/ucb )
/usr/bin:.:/usr/local/bin:/usr/ucb
The same is true of CDPATH and cdpath:
/usr:/u/pfalstad:/u/pfalstad/zsh
% CDPATH=/u/subbarao:/usr/src:/tmp
/u/subbarao /usr/src /tmp
In general, parameters with names in all lowercase are
arrays; assignments to them take the form:
Parameters with names in all uppercase are strings. If
there is both an array and a string version of the same
parameter, the string version is a colon-separated list,
HISTFILE is the name of the history file, where the history
is saved when a shell exits.
phoenix% HISTFILE=/tmp/history
Fri May 24 05:39:35 EDT 1991
5:39am up 4 days, 20:02, 40 users, load average: 2.30, 2.20, 2.00
the command cat is normally assumed:
Thus, you can view a file simply by typing:
However, this is not csh or sh compatible. To correct this,
change the value of the parameter NULLCMD, which is cat by
-rw-r--r-- 1 pfalstad 0 May 24 05:41 file
If NULLCMD is unset, the shell reports an error if no com-
mand is specified (like csh).
zsh: redirection with no command
Actually, READNULLCMD is used whenever you have a null com-
mand reading input from a single file. Thus, you can set
READNULLCMD to more or less rather than cat. Also, if you
set NULLCMD to : for sh compatibility, you can still read
files with < file if you leave READNULLCMD set to more.
The default prompt for zsh is:
The %m stands for the short form of the current hostname,
and the %# stands for a % or a #, depending on whether the
shell is running as root or not. zsh supports many other
control sequences in the PROMPT variable.
%h represents the number of current history event.
10 ~/etc/TeX/zsh apple-gunkies.gnu.ai.mit.edu>
11 ~/etc/TeX/zsh apple-gunkies>
Also available is the RPROMPT parameter. If this is set,
the shell puts a prompt on the right side of the screen.
% PROMPT='%l %T %m[%h] ' RPROMPT=' %~'
p0 6:15 phoenix[5] ~/etc/TeX/zsh
These special escape sequences can also be used with the -P
The POSTEDIT parameter is printed whenever the editor exits.
This can be useful for termcap tricks. To highlight the
prompt and command line while leaving command output
You can specify login or logout events to monitor by setting
the watch variable. Normally, this is done by specifying a
% watch=( pfalstad subbarao sukthnkr egsirer )
The log command reports all people logged in that you are
pfalstad has logged on p0 from mickey.
pfalstad has logged on p5 from mickey.
subbarao has logged on p8 from phoenix.
subbarao has logged off p8 from phoenix.
sukthnkr has logged on p8 from dew.
sukthnkr has logged off p8 from dew.
If you specify hostnames with an @ prepended, the shell will
watch for all users logging in from the specified host.
% watch=( @mickey @phoenix )
djthongs has logged on q2 from phoenix.
pfalstad has logged on p0 from mickey.
pfalstad has logged on p5 from mickey.
If you give a tty name with a % prepended, the shell will
watch for all users logging in on that tty.
% watch=( %ttyp0 %console )
root has logged on console from .
pfalstad has logged on p0 from mickey.
The format of the reports may also be changed.
% watch=( pfalstad gettes eps djthongs jcorr bdavis )
jcorr has logged on tf from 128.112.176.3:0.
jcorr has logged on r0 from 128.112.176.3:0.
gettes has logged on p4 from yo:0.0.
djthongs has logged on pe from grumpy:0.0.
djthongs has logged on q2 from phoenix.
bdavis has logged on qd from BRUNO.
eps has logged on p3 from csx30:0.0.
pfalstad has logged on p0 from mickey.
pfalstad has logged on p5 from mickey.
% WATCHFMT='%n on tty%l from %M'
jcorr on ttytf from 128.112.176.3:0.
jcorr on ttyr0 from 128.112.176.3:0.
gettes on ttyp4 from yo:0.0
djthongs on ttype from grumpy:0.0
djthongs on ttyq2 from phoenix.Princeto
bdavis on ttyqd from BRUNO.pppl.gov
eps on ttyp3 from csx30:0.0
pfalstad on ttyp0 from mickey.Princeton
pfalstad on ttyp5 from mickey.Princeton
% WATCHFMT='%n %a at %t %w.'
jcorr logged on at 3:15pm Mon 20.
jcorr logged on at 3:16pm Wed 22.
gettes logged on at 6:54pm Wed 22.
djthongs logged on at 7:19am Thu 23.
djthongs logged on at 7:20am Thu 23.
bdavis logged on at 12:40pm Thu 23.
eps logged on at 4:19pm Thu 23.
pfalstad logged on at 3:39am Fri 24.
pfalstad logged on at 3:42am Fri 24.
If you have a .friends file in your home directory, a con-
venient way to make zsh watch for all your friends is to do
% watch=( $(< ~/.friends) )
subbarao maruchck root sukthnkr ...
If watch is set to all, then all users logging in or out
Some options have already been mentioned; here are a few
Using the AUTOCD option, you can simply type the name of a
directory, and it will become the current directory.
With CDABLEVARS, if the argument to cd is the name of a
parameter whose value is a valid directory, it will become
CORRECT turns on spelling correction for commands, and the
CORRECTALL option turns on spelling correction for all argu-
zsh: correct `sl' to `ls' [nyae]? y
zsh: correct `x.v11r4' to `X.V11R4' [nyae]? n
/usr/princton/src/x.v11r4 not found
zsh: correct to `/etc/paswd' to `/etc/passwd' [nyae]? y
If you press y when the shell asks you if you want to
correct a word, it will be corrected. If you press n, it
will be left alone. Pressing a aborts the command, and
pressing e brings the line up for editing again, in case you
agree the word is spelled wrong but you don't like the
Normally, a quoted expression may contain a newline:
With CSHJUNKIEQUOTES set, this is illegal, as it is in csh.
GLOBDOTS lets files beginning with a . be matched without
explicitly specifying the dot.
.exrc .pnewsexpert .xserverrc
.mushexpert .xinitrc Mailboxes
HISTIGNOREDUPS prevents the current line from being saved in
the history if it is the same as the previous one; HISTIG-
NORESPACE prevents the current line from being saved if it
39> setopt histignoredups
42> setopt histignorespace
IGNOREBRACES turns off csh-style brace expansion.
IGNOREEOF forces the user to type exit or logout, instead of
INTERACTIVECOMMENTS turns on interactive comments; comments
% setopt interactivecomments
% date # this is a comment
Fri May 24 06:54:14 EDT 1991
NOCLOBBER prevents you from accidentally overwriting an
% cat /dev/null >~/.zshrc
zsh: file exists: /u/pfalstad/.zshrc
If you really do want to clobber a file, you can use the >!
operator. To make things easier in this case, the > is
stored in the history list as a >!:
% cat /dev/null >! ~/.zshrc
% cat /etc/motd > ~/.zshrc
zsh: file exists: /u/pfalstad/.zshrc
cat /etc/motd >! ~/.zshrc
RCQUOTES lets you use a more elegant method for including
single quotes in a singly quoted string:
% echo '"don'\''t do that."'
% echo '"don''t do that."'
% echo '"don''t do that."'
Finally, SUNKEYBOARDHACK wins the award for the strangest
option. If a line ends with `, and there are an odd number
of them on the line, the shell will ignore the trailing `.
This is provided for keyboards whose RETURN key is too
small, and too close to the ` key.
Fri May 24 06:55:38 EDT 1991
I would be happy to receive mail if anyone has any tricks or
ideas to add to this document, or if there are some points
that could be made clearer or covered more thoroughly.
Please notify me of any errors in this document.
projects / unix-history / blob