An Introduction to the Z Shell

This file is an Introduction to the Z Shell, by Paul Falstad. It was converted from the original intro.troff file distributed with zsh v2.2.0. The conversion was done by Jonathan Hardwick, jch@cs.cmu.edu, who would love to hear of any errors he introduced or texinfo rules he broke. The text remains the work of Paul Falstad.

Introduction

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.

Filename Generation

Otherwise known as globbing, filename generation is quite extensive in zsh. Of course, it has all the basics:

% ls
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
% ls *.c
foo.c  q.c
% ls *.[co]
bar.o   foo.c   foo.o   main.o  q.c
% ls foo.?
foo.c  foo.o
% ls *.[^c]
bar.o   file.h  foo.o   main.h  main.o
% ls *.[^oh]
foo.c  q.c

Also, if the EXTENDEDGLOB option is set, some new features are activated. For example, the ^ character negates the pattern following it:

% setopt extendedglob
% ls -d ^*.c
Makefile   file.pro   link       morestuff  run2       run303
bar.o      foo        main.h     pipe       run234     stuff
file.h     foo.o      main.o     run123     run240     sub
% ls -d ^*.*
Makefile   link       pipe       run2       run240     stuff
foo        morestuff  run123     run234     run303     sub
% ls -d ^Makefile
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
% ls -d *.^c
.rhosts   bar.o     file.h    file.pro  foo.o     main.h    main.o

An expression of the form matches a range of integers:

% ls run<200-300>
run234  run240
% ls run<300-400>
run303
% ls run<-200>
run123  run2
% ls run<300->
run303
% ls run<>
run123  run2    run234  run240  run303

Grouping is possible:

% ls (foo|bar).*
bar.o  foo.c  foo.o
% ls *.(c|o|pro)
bar.o     file.pro  foo.c     foo.o     main.o    q.c

Also, the string **/ forces a recursive search of subdirectories:

% ls -R
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

morestuff:

stuff:
file  xxx   yyy

stuff/xxx:
foobar

stuff/yyy:
frobar
% ls **/*bar
stuff/xxx/foobar  stuff/yyy/frobar
% ls **/f*
file.h            foo               foo.o             stuff/xxx/foobar
file.pro          foo.c             stuff/file        stuff/yyy/frobar
% ls *bar*
bar.o
% ls **/*bar*
bar.o             stuff/xxx/foobar  stuff/yyy/frobar
% ls stuff/**/*bar*
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.

% ls *.c
foo.c    foob.c    bar.c
% ls *.c~bar.c
foo.c    foob.c
% ls *.c~f*
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

pattern(...)

with single-letter qualifiers inside the parentheses.

% alias l='ls -dF'
% l *
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
% l *(/)
morestuff/  stuff/
% l *(@)
link@
% l *(*)
foo*        link@       morestuff/  stuff/
% l *(x)
foo*        link@       morestuff/  stuff/
% l *(X)
foo*        link@       morestuff/  stuff/
% l *(R)
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 writable files. *(W) is especially important, since it checks for world-writable files:

% l *(w)
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/
% l *(W)
link@   run240
% l -l link run240
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:

% l *(W^@)
run240
% l *(x)
foo*        link@       morestuff/  stuff/
% l *(x^@/)
foo*

To find all plain files, you can use .:

% l *(.)
Makefile  file.h    foo*      foo.o     main.o    run123    run234    run303
bar.o     file.pro  foo.c     main.h    q.c       run2      run240    sub
% l *(^.)
link@       morestuff/  pipe        stuff/
% l s*(.)
stuff/   sub
% l *(p)
pipe
% l -l *(p)
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):

% l -l *(^U)
-rw-------  1 subbarao       29 May 23 18:13 sub

This searches for setuid files:

% l -l *(s)
-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
% l -l *(u3338)
-rw-------  1 subbarao       29 May 23 18:13 sub

Startup Files

There are five startup files that zsh will read commands from:

$ZDOTDIR/.zshenv
$ZDOTDIR/.zprofile
$ZDOTDIR/.zshrc
$ZDOTDIR/.zlogin
$ZDOTDIR/.zlogout

If ZDOTDIR is not set, then the value of HOME is used; this is the usual case.

.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 variables. .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 bindings, etc.

.zlogin is sourced in login shells. It should contain commands that should be executed only in login shells. .zlogout is sourced when login shells exit. .zprofile is similar 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 (fortune, msgs, etc).

Shell Functions

zsh also allows you to create your own commands by defining shell functions. For example:

% yp () {
>       ypmatch $1 passwd.byname
> }
% yp pfalstad
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:

% function yp {
>       ypmatch $1 passwd.byname
> }
% function yp () {
>       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:

% alias ypmatch=echo
% yp pfalstad
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 }
% yp pfalstad
pfalstad passwd.byname

it is parsed with the new alias definition in place. Therefore, in general you must define aliases before functions.

We can make the function take multiple arguments:

% unalias ypmatch
% yp () {
>       for i
>       do ypmatch $i passwd.byname
>       done
> }
% 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 given:

% yp () {
>       if (( $# == 0 ))
>       then echo usage: yp name ...; fi
>       for i; do ypmatch $i passwd.byname; done
> }
% yp
usage: yp name ...
% yp pfalstad sukthnkr
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:

% randline () {
>       integer z=$(wc -l <$1)
>       sed -n $[RANDOM % z + 1]p $1
> }
% randline /etc/motd
PHOENIX WILL BE DOWN briefly Friday morning, 5/24/91 from 8 AM to
% randline /etc/motd
SunOS Release 4.1.1 (PHOENIX) #19: Tue May 14 19:03:15 EDT 1991
% randline /etc/motd
| Please use the "msgs" command to read announcements.  Refer to the   |
% echo $z

%

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 builtin:

% functions randline
randline () {
        integer z=$(wc -l <$1)
        sed -n $[RANDOM % z + 1]p $1

}
% functions
yp () {
        if let $# == 0 
        
        then
                echo usage: yp name ...
        
        fi
        for i
        do
                ypmatch $i passwd.byname
        
                done

}
randline () {
        integer z=$(wc -l <$1)
        sed -n $[RANDOM % z + 1]p $1

}

Here's another one:

% cx () { chmod +x $* }
% ls -l foo bar
-rw-r--r--  1 pfalstad       29 May 24 04:38 bar
-rw-r--r--  1 pfalstad       29 May 24 04:38 foo
% cx foo bar
% ls -l foo bar
-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:

% chmod 644 foo bar
% alias cx='chmod +x'
% cx foo bar
% ls -l foo bar
-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 it into memory.

% mkdir /tmp/funs
% cat >/tmp/funs/yp
ypmatch $1 passwd.byname
^D
% cat >/tmp/funs/cx
chmod +x $*
^D
% FPATH=/tmp/funs
% autoload cx yp
% functions cx yp
undefined cx ()
undefined yp ()
% chmod 755 /tmp/funs/{cx,yp}
% yp egsirer
egsirer:*:3214:35:Emin Gun Sirer:/u/egsirer:/bin/sh
% functions yp
yp () {
        ypmatch $1 passwd.byname
}

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 process is not created.)

% ed /tmp/funs/yp
25
i
#! /usr/local/bin/zsh
.
w
42
q
% 

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 scripts.

Directories


One nice feature of zsh is the way it prints directories.  For example,
if we set the prompt like this:

phoenix% PROMPT='%~> '
~> cd src
~/src>


the shell will print the current directory in the prompt, using the
~ character.  However, zsh is smarter than most other shells in
this respect:

~/src> cd ~subbarao
~subbarao> cd ~maruchck
~maruchck> cd lib
~maruchck/lib> cd fun
~maruchck/lib/fun> foo=/usr/princeton/common/src
~maruchck/lib/fun> cd ~foo
~foo> cd ..
/usr/princeton/common> cd src
~foo> cd news/nntp
~foo/news/nntp> cd inews
~foo/news/nntp/inews>


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 convenient,
especially if you're sick of seeing prompts like this:

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
~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 this purpose:

~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
~spool> cd .msgs
~spool/.msgs>



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 xterm, this will work:



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 can do this:

% print -D $PWD
~subbarao/src


and to print each component of the path in short form:

% print -D $path
/bin /usr/bin ~locbin ~locbin/X11 ~/bin


Directory Stacks





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 directory off the stack and
changes to it.

phoenix% cd 
phoenix% PROMPT='Z %~> '
Z ~> pushd /tmp
/tmp ~
Z /tmp> pushd /usr/etc
/usr/etc /tmp ~
Z /usr/etc> pushd /usr/bin
/usr/bin /usr/etc /tmp ~
Z /usr/bin> popd
/usr/etc /tmp ~
Z /usr/etc> popd
/tmp ~
Z /tmp> pushd /etc
/etc /tmp ~
Z /etc> popd 
/tmp ~


zsh's directory stack commands work similarly.  One difference is the
way pushd is handled if no arguments are given.  As in csh, this
exchanges the top two elements of the directory stack:

Z /tmp> dirs
/tmp ~
Z /tmp> pushd
~ /tmp


unless the stack only has one entry:

Z ~> popd
/tmp
Z /tmp> dirs
/tmp
Z /tmp> pushd
~ /tmp


or unless the PUSHDTOHOME option is set:


Z ~> setopt pushdtohome
Z ~> pushd
~ ~ /tmp




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:

~> DIRSTACKSIZE=8
~> setopt autopushd pushdminus pushdsilent pushdtohome
~> alias dh='dirs -v'
~> cd /tmp
/tmp> cd /usr
/usr> cd bin
/usr/bin> cd ../pub
/usr/pub> dh
0       /usr/pub
1       /usr/bin
2       /usr
3       /tmp
4       ~
/usr/pub> cd -3
/tmp> dh
0       /tmp
1       /usr/pub
2       /usr/bin
3       /usr
4       ~
/tmp> ls =2/df
/usr/bin/df
/tmp> cd -4
~>


Note that =2 expanded to the second directory in the history
list, and that cd -3 recalled the third directory in the
list.



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
it's easier to type:

~> dh
0       ~
1       /tmp
2       /usr/pub
3       /usr/bin
4       /usr
~> unsetopt pushdminus
~> cd +1
/tmp> dh
0       /tmp
1       ~
2       /usr/pub
3       /usr/bin
4       /usr
/tmp> cd +2
/usr/pub>



PUSHDSILENT keeps the shell from printing the directory stack
each time we do a cd, and PUSHDTOHOME we mentioned
earlier:

/usr/pub> unsetopt pushdsilent
/usr/pub> cd /etc
/etc /usr/pub /tmp ~ /usr/bin /usr
/etc> cd
~ /etc /usr/pub /tmp ~ /usr/bin /usr
~> unsetopt pushdtohome
~> cd
/etc ~ /usr/pub /tmp ~ /usr/bin /usr
/etc>




DIRSTACKSIZE keeps the directory stack from getting too large,
much like HISTSIZE:

/etc> setopt pushdsilent
/etc> cd /
/> cd /
/> cd /
/> cd /
/> cd /
/> cd /
/> cd /
/> cd /
/> dh
0       /
1       /
2       /
3       /
4       /
5       /
6       /
7       /


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 to nest.

% ls -l `echo /vmunix`
-rwxr-xr-x  1 root      1209702 May 14 19:04 /vmunix
% ls -l $(echo /vmunix)
-rwxr-xr-x  1 root      1209702 May 14 19:04 /vmunix
% who | grep mad
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}'
ttyt7
ttyu1
ttyu6
ttyv3
% cd /dev; ls -l $(who |
> grep $(echo 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:

% ls -l `tty`
crw-rw-rw-  1 root      20,  28 May 23 18:35 /dev/ttyqc
% ls -l $TTY
crw-rw-rw-  1 root      20,  28 May 23 18:35 /dev/ttyqc
% ls -l `which rn`
-rwxr-xr-x  1 root       172032 Mar  6 18:40 /usr/princeton/bin/rn
% ls -l =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 convenient for you,
you can turn it off:

% ls
=foo    =bar
% ls =foo =bar
zsh: foo not found
% setopt noequals
% ls =foo =bar
=foo    =bar


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:

% print -l foo bar
foo
bar


We could also have written:

% who | fgrep -f =(echo 'root
> lemke
> shgchan
> subbarao')


Using process substitution, you can edit the output of a command:

% ed =(who | fgrep -f ~/.friends)
355
g/lemke/d
w /tmp/filbar
226
q
% cat /tmp/filbar
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)
43u/84 1: x
% ls -l /tmp/zsha06024
/tmp/zsha06024 not found




Note that the shell creates a temporary file, and deletes it when the
command is finished.

% diff =(ls) =(ls -F)
3c3
< fortune
---
> fortune*
10c10
< strfile
---
> strfile*


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 the
temporary file.

Aliasing


Often-used commands can be abbreviated with an alias:


% alias uc=uncompress
% ls
hanoi.Z
% uc hanoi
% ls
hanoi


or commands with certain desired options:

% alias fm='finger -m'
% fm root
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
No unread mail
No Plan.

% alias lock='lock -p -60000'
% lock
lock: /dev/ttyr4 on phoenix. timeout in 60000 minutes
time now is Fri May 24 04:23:18 EDT 1991
Key: 

% alias l='ls -AF'
% l /
.bash_history              kadb*
.bashrc                    lib@
.cshrc                     licensed/
.exrc                      lost+found/
.login                     macsyma
...


Aliases can also be used to replace old commands:

% alias grep=egrep ps=sps make=gmake
% alias whoami='echo root'
% whoami
root


or to define new ones:

% cd /
% alias sz='ls -l | sort -n +3 | tail -10'
% sz
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
% cd
% alias rable='ls -AFtrd *(R)' nrable='ls -AFtrd *(^R)'
% rable
README      func/       bin/        pub/        News/       src/
nicecolors  etc/        scr/        tmp/        iris/       zsh*
% nrable
Mailboxes/  mail/       notes


(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
% who | grep me
pfalstad ttyp0   May 24 03:39   (mickey.Princeton)
pfalstad ttyp5   May 24 03:42   (mickey.Princeton)
% fm gun
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
% ftp warc
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 ypmatch
pfalstad passwd:

% alias -g PASS='<(ypcat passwd)'
% grep pfalstad PASS
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 example, if you defined a
global alias called | (which is possible), zsh would begin to act
very strangely; every pipe symbol 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 arguments.  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 anything, although alias will return a nonzero exit
code.  The proper syntax is this:

alias rm='mv \!* /tmp/wastebasket'


However, this won't work either:

% rm foo.dvi
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:

% unalias rm
% rm () { mv $* /tmp/wastebasket }
% rm foo.dvi
% ls /tmp/wastebasket
foo.dvi


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:


% csh
csh> alias
l       ls -AF
more    less
on      last -2 !:1 ; who | grep !:1
csh> exit
% c2z >neat_zsh_aliases
% cat neat_zsh_aliases
alias l='ls -AF'
alias more='less'
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 settings
as closely as possible.  You could include its output in your
startup file, .zshrc.

History


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
setopt nobanghist.


Another way is to use the fc command.  For example, if you type
an erroneous command:

% for i in `cat /etc/clients` 
 do 
 rpu $i 
 done
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
ed).


% fc
49
/rpu/s//rup/p
 rup $i 
w
49
q
for i in `cat /etc/clients` 
 do 
 rup $i 
 done
        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
command, with optional changes:

% echo foo
foo
% r
echo foo
foo

% echo foo
foo
% r foo=bar
echo bar
bar


Command Line Editing


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 with @ctrl{P}
(control-P):

% ls ~
-           README      file        mail        pub         tmp
Mailboxes   bin         func        nicecolors  scr         zsh
News        etc         iris        notes       src
% echo foobar
foobar
% ^P
% echo foobar^P
% ls ~_


Pressing @ctrl{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:

% for i in a b c d e
> do
> echo $i
> done
a
b
c
d
e
% ^P
% for i in a b c d e 
 do 
 echo $i 
 done_


Now you can just move up to the part you want to change...

% for i in a_ b c d e
 do 
 echo $i 
 done


change it, and execute the new command.

% for i in f g h i j
 do 
 echo $i 
 done
f
g
h
i
j


Also, you can search the history for a certain command using
ESC-P:


% set ESC-P
% setopt autolist ESC-P
% setopt nocorrect_


Another way is to do an incremental search, emacs-style:



% ^R
% _
i-search:

% l_s /usr/bin
i-search: l

% date > foofil_e.c
i-search: le


Another useful feature of the editor is command and filename completion.






% compTAB
% compress _

% ls /nicTAB
% ls /nicecolors _

% ls /usr/prTAB
% ls /usr/princeton/_

% ls -l =comTAB
% ls -l =compress _


If the completion is ambiguous, the editor will beep.  You can list
possible completions by pressing @ctrl{D}:



% ls /vmuTAB beep
% ls /vmunix_
% ls /vmunix^D
vmunix                    vmunix.old                
vmunix.new.kernelmap.old  vmunix.org


Or, you could just set the AUTOLIST option:


% setopt autolist
% ls /vmuTAB beep
vmunix                    vmunix.old                
vmunix.new.kernelmap.old  vmunix.org
% ls /vmunix_



Another option you could set is RECEXACT, which causes exact
matches to be accepted, even if there are other possible
completions:

% setopt recexact
% ls /vmuTAB beep
vmunix                    vmunix.old                
vmunix.new.kernelmap.old  vmunix.org
% ls /vmunix_TAB
% ls /vmunix _



The fignore variable lists suffixes of files to ignore during
completion.

% ls fooTAB beep
foofile.c  foofile.o
% fignore=( .o \~ .bak .junk )
% ls fooTAB
% ls foofile.c _


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:



% ls ~pfalTAB
% ls ~pfalstad/_


and parameter name completion:



% echo $ORGTAB
% echo $ORGANIZATION _


and hostname completion, if you give the shell a list of hosts to
complete:




% hosts=( phoenix.princeton.edu uunet.uu.net nic.ddn.mil
> diskfarm.princeton.edu gnu.ai.mit.edu
> eniac.seas.upenn.edu )
% telnet diskTAB
% telnet diskfarm.princeton.edu _

% ftp uuTAB
% ftp uunet.uu.net _

% mail subbarao@phTAB
% mail subbarao@phoenix.princeton.edu _


and option completion:



% setopt noclTAB
% setopt noclobber _


and binding completion:



% bindkey '^X^X' puTAB
% bindkey '^X^X' push-line _



The compctl command is used to control how completion works.  For
example, to specify that certain commands show take commands as
arguments, you use compctl -c:

% compctl -c man nohup
% man uptTAB
% man uptime _


To specify that a command should complete filenames, you should use
compctl -f.  This is the default.  It can be combined with
-c, as well.

% compctl -cf echo
% echo uptTAB
% echo uptime _

% echo foTAB
% echo foo.c


Similarly, use -h to specify hostnames, -o to specify
options, -v to specify variables, and -b to specify
bindings.

% compctl -h rlogin
% compctl -hfc rsh
% compctl -b bindkey


You can also use -k to specify a custom list of keywords to use
in completion.


% ftphosts=(ftp.uu.net wuarchive.wustl.edu)
% compctl -k ftphosts ftp
% ftp wuTAB
% ftp wuarchive.wustl.edu _

% friends=(cpirazzi subbarao sukthnkr)
% compctl -k friends mail finger su
% finger cpTAB
% finger cpirazzi _


In addition to completion, TAB performs expansion if possible.



% ls *.cTAB
% ls foofile.c fortune.c rnd.c strfile.c unstr.c_


For example, suppose you have a bunch of weird files in an important
directory:



% ls
  * * *       ; & % $??foo  dspfok        foo.c
  !"foo"!       ` \ `         foo           rrr


You want to remove them, but you don't want to damage foo.c.
Here is one way to do this:

% rm *TAB
% 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 \kxr\l'|\nxu\(ul'rr


and press return.  Everything except foo.c will be deleted from
the directory.

Here's another trick; let's say you have typed this command in:

% 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 commands.  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 executing 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 command.
This can be done by recalling the line with @ctrl{P} and pressing
ESC-' again:

% 'echo '\''don'\''\'\'''\''t do that; type '\''\'\'''\''rm -rf
\*'\''\'\'''\'', with a \ before the *.'\'''


and then move to the beginning and add the command to create an alias.

% alias zoof='echo '\''don'\''\'\'''\''t do that; type '\''\'\'''\''
rm -rf \*'\''\'\'''\'', with a \ before the *.'\'''
% zoof
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:



% setopt menucomplete
% ls /vmuTAB
% ls /vmunixTAB
% ls /vmunix.new.kernelmap.oldTAB
% ls /vmunix.old_


Each time you press TAB, it displays the next possible completion.
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 ambiguous completion will cycle
through the possible completions.

Bindings


Each of the above editor commands was actually a function bound by
default to a certain key.  The real names of the commands are:

expand-or-complete   TAB
push-line            ESC-Q
run-help             ESC-H
accept-and-hold      ESC-A
quote-line           ESC-'









These bindings are arbitrary; you could change them if you want.  For
example, to bind accept-line to @ctrl{Z}:

% bindkey '^Z' accept-line


Another idea would be to bind the delete key to delete-char; this
might be convenient if you use @ctrl{H} for backspace.


% bindkey '^?' delete-char


Or, you could bind @ctrl{X}@ctrl{H} to run-help:

% bindkey '^X^H' run-help


Other examples:

% bindkey '^X^Z' universal-argument
% bindkey ' ' magic-space
% bindkey -s '^T' 'uptime
> '




universal-argument multiplies the next command by 4.  Thus
@ctrl{X}@ctrl{Z}@ctrl{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 you press
@ctrl{T}.


If you have a NeXT keyboard, the one with the | and \ keys
very inconveniently placed, the following bindings may come in
handy:

% bindkey -s '\/' '\\'
% bindkey -s '\=' '|'




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
mail, etc.

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 vared
command:

% vared PATH
> /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 contents of the
edit buffer will be assigned to PATH.


Parameter Substitution



In zsh, parameters are set like this:

% foo=bar
% echo $foo
bar


Spaces before or after the = are frowned upon:

% foo = bar
zsh: command not found: foo


Also, set doesn't work for setting parameters:


% set foo=bar
% set foo = bar
% echo $foo

%


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,
etc.).




% set foo=bar
% echo $1
foo=bar
% set foo = bar
% echo $3 $2
bar =


If you're really intent on using the csh syntax, define a function like
this:


% set () {
>    eval "$1$2$3"
> }
% set foo = bar
% set fuu=brrr
% echo $foo $fuu
bar brrr


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 parameters like it
should.  To get around that you need a case statement:

% set () {
>    case $1 in
>    -*|+*|'') builtin set $* ;;
>    *) eval "$1$2$3" ;;
>    esac
> }


For the most part, this should make csh users happy.

The following sh-style operators are supported in zsh:



% unset null
% echo ${foo-xxx}
bar
% echo ${null-xxx}
xxx
% unset null
% echo ${null=xxx}
xxx
% echo $null
xxx
% echo ${foo=xxx}
bar
% echo $foo
bar
% unset null
% echo ${null+set}

% echo ${foo+set}
set


Also, csh-style : modifiers may be appended to a parameter


substitution.

% echo $PWD
/home/learning/pf/zsh/zsh2.00/src
% echo $PWD:h
/home/learning/pf/zsh/zsh2.00
% echo $PWD:h:h
/home/learning/pf/zsh
% echo $PWD:t
src
% name=foo.c
% echo $name
foo.c
% echo $name:r
foo
% echo $name:e
c




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 :
modifiers:

% echo ${PWD%/*}
/home/learning/pf/zsh/zsh2.00
% echo ${PWD%/*/*}
/home/learning/pf/zsh
% echo ${PWD##*/}
src
% echo ${name%.*}
foo
% echo ${name#*.}
c


zsh also has upper/lowercase modifiers:



% xx=Test
% echo $xx:u
TEST
% echo $xx:l
test


and a substitution modifier:



% echo $name:s/foo/bar/
bar.c
% ls
foo.c    foo.h    foo.o    foo.pro
% for i in foo.*; mv $i $i:s/foo/bar/
% ls
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'
% ls $srcs
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:

$ ll () { ls -F $* }
$ ll 'fuu bar'
fuu not found
bar not found

% ll 'fuu bar'
fuu bar not found


Of course, a hackish workaround is available in sh (and zsh):

% setopt shwordsplit
% ll () { ls -F "$@" }
% ll 'fuu bar'
fuu bar not found


If you like the sh behaviour, zsh can accomodate you:

% ls ${=srcs}
exec.c  glob.c  init.c
% setopt shwordsplit
% ls $srcs
exec.c  glob.c  init.c


Another way to get the $srcs trick to work is to use an array:


% unset srcs
% srcs=( glob.c exec.c init.c )  
% ls $srcs
exec.c  glob.c  init.c


or an alias:

% alias -g SRCS='exec.c glob.c init.c'
% ls SRCS
exec.c  glob.c  init.c


Another option that modifies parameter expansion is RCEXPANDPARAM:


% echo foo/$srcs
foo/glob.c exec.c init.c
% setopt rcexpandparam
% echo foo/$srcs
foo/glob.c foo/exec.c foo/init.c
% echo foo/${^srcs}
foo/glob.c foo/exec.c foo/init.c
% echo foo/$^srcs
foo/glob.c foo/exec.c foo/init.c


Shell Parameters



The shell has many predefined parameters that may be accessed.  Here are
some examples:






% sleep 10 &
[1] 3820
% echo $!
3820
% set a b c
% echo $#
3
% echo $ARGC
3
% ( exit 20 ) ; echo $?
20
% false; echo $status
1


($? and $status are equivalent.)







% echo $HOST $HOSTTYPE
dendrite sun4
% echo $UID $GID
701 60
% cd /tmp
% cd /home
% echo $PWD $OLDPWD
/home /tmp
% ls $OLDPWD/.getwd 
/tmp/.getwd


~+ and ~- are short for $PWD and $OLDPWD, 
respectively.






% ls ~-/.getwd
/tmp/.getwd
% ls -d ~+/learning
/home/learning
% echo $RANDOM
4880
% echo $RANDOM
11785
% echo $RANDOM
2062
% echo $TTY
/dev/ttyp4
% echo $VERSION
zsh v2.00.03
% echo $USERNAME
pf




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 )
% ls /usr
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
% cd spool
/usr/spool
% cd bin
/usr/bin
% cd func
~/func
% cd 
% cd pub
% pwd
/u/pfalstad/pub
% ls -d /usr/pub
/usr/pub




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:.
% echo $path
/bin /usr/bin /tmp .
% path=( /usr/bin . /usr/local/bin /usr/ucb )
% echo $PATH
/usr/bin:.:/usr/local/bin:/usr/ucb


The same is true of CDPATH and cdpath:



% echo $CDPATH
/usr:/u/pfalstad:/u/pfalstad/zsh
% CDPATH=/u/subbarao:/usr/src:/tmp
% echo $cdpath
/u/subbarao /usr/src /tmp



In general, parameters with names in all lowercase are arrays;
assignments to them take the form:

name=(elem ...)



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, like PATH.




HISTFILE is the name of the history file, where the history is
saved when a shell exits.

% zsh
phoenix% HISTFILE=/tmp/history
phoenix% SAVEHIST=20
phoenix% echo foo
foo
phoenix% date
Fri May 24 05:39:35 EDT 1991
phoenix% uptime
  5:39am  up 4 days, 20:02,  40 users,  load average: 2.30, 2.20, 2.00
phoenix% exit
% cat /tmp/history
HISTFILE=/tmp/history
SAVEHIST=20
echo foo
date
uptime
exit
% HISTSIZE=3
% history
   28  rm /tmp/history
   29  HISTSIZE=3
   30  history


In zsh, if you say

% >file


the command cat is normally assumed:

% >file
foo!    
^D
% cat file
foo!


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 default.


% NULLCMD=:
% >file
% ls -l file
-rw-r--r--  1 pfalstad        0 May 24 05:41 file


If NULLCMD is unset, the shell reports an error if no command is
specified (like csh).

% unset NULLCMD
% >file
zsh: redirection with no command



Actually, READNULLCMD is used whenever you have a null command
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.

Prompting


The default prompt for zsh is:

phoenix% echo $PROMPT
%m%# 


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.

% PROMPT='%/> '
/u/pfalstad/etc/TeX/zsh>

% PROMPT='%~> '   
~/etc/TeX/zsh> 

% PROMPT='%h %~> '
6 ~/etc/TeX/zsh> 


%h represents the number of current history event.

% PROMPT='%h %~ %M> '
10 ~/etc/TeX/zsh apple-gunkies.gnu.ai.mit.edu> 

% PROMPT='%h %~ %m> '
11 ~/etc/TeX/zsh apple-gunkies> 

% PROMPT='%h %t> '
12 6:11am> 

% PROMPT='%n %w tty%l>'
pfalstad Fri 24 ttyp0>



Also available is the RPROMPT parameter.  If this is set, the
shell puts a prompt on the right side of the screen.

% RPROMPT='%t'
%                                                      6:14am

% RPROMPT='%~'
%                                               ~/etc/TeX/zsh

% 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
option to print:


% print -P %h tty%l
15 ttyp1



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 unhighlighted, try
this:

% POSTEDIT=`echotc se`
% PROMPT='%S%% '


Login/Logout Watching



You can specify login or logout events to monitor by setting the
watch variable.  Normally, this is done by specifying a list of
usernames.

% watch=( pfalstad subbarao sukthnkr egsirer )



The log command reports all people logged in that you are
watching for.

% log
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 )
% log
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 )
% log
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 )
% log
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'
% log
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 BRUNOpl.gov
eps on ttyp3 from csx30:0.0
pfalstad on ttyp0 from mickey.Princeton
pfalstad on ttyp5 from mickey.Princeton
% WATCHFMT='%n fm %m'
% log
jcorr fm 128.112.176.3:0
jcorr fm 128.112.176.3:0
gettes fm yo:0.0
djthongs fm grumpy:0.0
djthongs fm phoenix
bdavis fm BRUNO
eps fm csx30:0.0
pfalstad fm mickey
pfalstad fm mickey
% WATCHFMT='%n %a at %t %w.'
% log
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 convenient
way to make zsh watch for all your friends is to do this:
% watch=( $(< ~/.friends) )
% echo $watch
subbarao maruchck root sukthnkr ...


If watch is set to all, then all users logging in or out
will be reported.

Options


Some options have already been mentioned; here are a few more:

% cd /
% setopt autocd
% bin
% pwd
/bin
% ../etc
% pwd
/etc



Using the AUTOCD option, you can simply type the name of a
directory, and it will become the current directory.

% setopt cdablevars
% foo=/tmp
% cd foo
/tmp




With CDABLEVARS, if the argument to cd is the name of a
parameter whose value is a valid directory, it will become the current
directory.





CORRECT turns on spelling correction for commands, and the
CORRECTALL option turns on spelling correction for all arguments.

% setopt correct
% sl
zsh: correct `sl' to `ls' [nyae]? y
% setopt correctall
% ls x.v11r4
zsh: correct `x.v11r4' to `X.V11R4' [nyae]? n
/usr/princton/src/x.v11r4 not found
% ls /etc/paswd
zsh: correct to `/etc/paswd' to `/etc/passwd' [nyae]? y
/etc/passwd


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 correction.

Normally, a quoted expression may contain a newline:

% echo '
> foo
> '

foo

%



With CSHJUNKIEQUOTES set, this is illegal, as it is in csh.

% setopt cshjunkiequotes
% ls 'foo
zsh: unmatched '




GLOBDOTS lets files beginning with a . be matched without
explicitly specifying the dot.

% ls -d *x*
Mailboxes
% setopt globdots
% ls -d *x*
.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; HISTIGNORESPACE
prevents the current line from being saved if it begins with a space.

% PROMPT='%h> '
39> setopt histignoredups
40> echo foo
foo
41> echo foo
foo
41> echo foo
foo
41> echo bar
bar
42> setopt histignorespace
43>  echo foo
foo
43>  echo fubar
fubar
43>  echo fubar
fubar


IGNOREBRACES turns off csh-style brace expansion.




% echo x{y{z,a},{b,c}d}e
xyze xyae xbde xcde
% setopt ignorebraces
% echo x{y{z,a},{b,c}d}e
x{y{z,a},{b,c}d}e


IGNOREEOF forces the user to type exit or logout,
instead of just pressing @ctrl{D}.


% setopt ignoreeof
% ^D
zsh: use 'exit' to exit.


INTERACTIVECOMMENTS turns on interactive comments; comments begin
with a #.

% setopt interactivecomments
% date # this is a comment
Fri May 24 06:54:14 EDT 1991


NOCLOBBER prevents you from accidentally overwriting an existing
file.

% setopt noclobber
% 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."'
"don't do that."
% echo '"don''t do that."'
"dont do that."
% setopt rcquotes
% echo '"don''t do that."'
"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.

% setopt sunkeyboardhack
% date`
Fri May 24 06:55:38 EDT 1991


Closing Comments

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.

Concept Index


.friends
.zlogin
.zlogout
.zprofile
.zshenv
.zshrc
NeXT
Sun keyboard
VMS
ZLE
alias, csh
alias, expansion
alias, global
alias, global, perils of
aliasing
arrays
binding completion
bindings
brace expansion, csh
buffer stack
case modifiers
command completion
command substitution
completion, binding
completion, command
completion, custom
completion, filename
completion, hostname
completion, option
completion, parameter name
completion, username
completions, possible
correction, spelling
csh aliases
csh brace expansion
csh modifiers
custom completion
directories
directory history
directory stacks
emacs mode
expansion
file, history
filename completion
filename generation
files, startup
files, temporary
files, wierd
functions
generation, filename
global aliases
globbing
globbing, matching . files
grouping
history
history file
history, directory
history, incremental search
history, options
history, searching
hostname completion
ksh modifiers
login/logout watching
mode, emacs
mode, vi
modifiers, case
modifiers, csh
modifiers, ksh
modifiers, subsitution
operators, sh
option completion
options
parameter name completion
parameter substitution
parameter substitution, splitting
parameters, positional
parameters, shell
positional parameters
print, options
process substitution
prompting
qualifiers
quoting
recursive search
scripts
search, recursive
sh operators
shell parameters
spelling correction
stack, buffer
stacks, directory
startup files
strings
subsitution, command
subsitution, process
substitution modifier
substitution, parameter
substitution, parameter, splitting
substitution, process
temporary files
title bar, xterm
username completion
vi mode
wierd files
xterm, title bar


Variables Index


#!
$#
$1
$2
$?
$ARGC
$GID
$HOST
$HOSTTYPE
$OLDPWD
$PWD
$RANDOM
$TTY
$UID
$USERNAME
$VERSION
$cdpath
$status
AUTOCD
AUTOLIST
AUTOMENU
AUTOPUSHD
CDABLEVARS
CDPATH
CORRECT
CORRECTALL
CSHJUNKIEQUOTES
DIRSTACKSIZE
EXTENDEDGLOB
GLOBDOTS
HISTFILE
HISTIGNOREDUPS
HISTIGNORESPACE
HISTSIZE
HOME
IGNOREBRACES
IGNOREEOF
INTERACTIVECOMMENTS
MENUCOMPLETE
NOCLOBBER
NULLCMD
PATH
POSTEDIT
PROMPT
PUSHDMINUS
PUSHDSILENT
PUSHDTOHOME
RCEXPANDPARAM
RCQUOTES
READNULLCMD
RECEXACT
RPROMPT
SUNKEYBOARDHACK
ZDOTDIR
cdpath
fignore
hosts
path
watch
~+
~-


Functions Index


accept-and-hold
alias
autoload
bindkey
c2z
case
cat
cd
chpwd
compctl
echo
expand-or-complete
fc
function
functions
log
magic-space
namedir
popd
print
push-line
pushd
quote-line
r
randline
run-help
set
set, csh-style
universal-argument
vared


Key Index


ALT-/
ALT-=
CTRL-D
CTRL-H
CTRL-P
CTRL-R
ESC-A
ESC-H
ESC-P
ESC-Q
TAB