The Z-Shell (ZSH) Lovers' Page

Latest change: Sat Nov 22 21:44:36 CET 2003

An abstract description of the ZSHELL's features.

The ZSH is a great shell (aka "command line interpreter") which can make it a lot easier for beginners. However, even the Linux community has not really discovered it yet even though it has considerable advantages over bash and tcsh and a lot in common with sh and ksh.

This page lists describes some of ZSH's features to give you an idea of what is possible. Hopefully this is an alternative to your reading the fine manual - which, by the way, has almost 19,00 lines on an 80 column terminal for zsh 4.1.1.

have a lot of fun!

Sven Guckes         webpage-zsh-lover(at)guckes.net
Matthias Kopfermann matthi(at)infodrom.north.de

Notation

The string [zsh] is presented at the start of line to indicate that the following command is entered with a ZSH. It's just a precaution in case other examples are presented with eg the bash or the ksh.

"EOL" stands for "end-of-line".

Shell Name Abbreviations:
• sh - Bourne Shell
• csh - C-Shell
• ksh - Korn Shell
• tcsh - see "THE T IN TCSH" in the manual.

Special Characters
• "ESC" stands for the "escape" key
• "C-A" and "^A" stand for "Control-A"

Compatibility. The ZSH is based on ksh and also includes some features of bash and tcsh. There are many books on shells and shell scripting so there is lots of information about how this kind of program works and can be handled.

Emulation Modes. For those who already know the basic shells (sh, csh, ksh) there are emulation modes which tune the zsh such that it behaves just like one of them, eg with emulate sh . (see the zshbuiltins manual, section "emulate" ). [link!] Mind you, the emulation is not perfect. But it certainly eases its use if you have used other shells before.

Configurability! The ZSH has over 130 options which allows adaption to the user's preferences and a lot of flexibility.

Modularity. The ZSH is modular. You can leave out all the modules and thus get a shell with a lot less memory than eg bash.

Expandability. There are a lot of expansion commands. This allows to expand command prefixes *and* parameter prefixes, prefixes of files and directory name, as well as expansion on environment variables,

[Programmable expansion have been available since bash 2.04 since April 2000. However, the ksh does not have that feature at all.]

Command Completion

Instead of using a lot of extra options you can now adjust the shell's expansions with the use of functions. This also means that you can quickly generate more completions by simply editing existing ones. And ZSH already ships with quite a few completions, eg try xterm -fn <TAB>.

More examples for completions [using the old scheme up to 3.1.5]:
compctl -g '*(/)' cd - this makes "cd" complete on subdirs only.
compctl -k '(`command`)' - this allows to complete on all sorts of useful things, eg complete on email addresses for the mailer or on ftp addresses for the ftp client.
compctl -g '*.class(:r)' java - this will chop off the file extension on completion which is useful eg with the java compiler. (who would otherwise try to open "foo.class.class").

Global Aliases

An alias name will only be expanded when it is the first word within the command. However, a global alias will also be expanded when it occurs elsewhere. Example: alias -g L=' |less' this allows to enter 'L' at the end of a command chain to get the output piped to the "less" pager:

[zsh] cut -d: -f 5 /etc/passwd | sed 's/ .*//' | sort | uniq -c | sort -n L

Filename Exclusions. The filename patterns are good for finding complicated matches, however, there is usually no way to *exclude* some matches. ZSH however allows the '^' to be used as a NOT operator, meaning "match all dirs/files *not* matching the following pattern". For example, ^(bar|foo) would leave out "bar" and "foo" from the list of all dirs+files in the current directory. More specifically, ls ^(*.bz2|*.gz) would list all dirs+files not ending in either ".bz2" or ".gz". ZSH allows to take away matches with the '~' character. This requires setopt extended_glob to be set.

Furthermore, grep foo bar*~(*.gz|*.bz|*.bz2|*.zip|*.Z) searches for "foo" in all files starting with "bar" except those with an extension which indicates that the data has been compressed.

As this list of extensions is already quote long for typing you might want to abbreviate it with a global alias. Make sure that the global aliases have a unique name; It's probably best to use an unusual character as their initial, eg the '§'.

Use unalias '§k' to get rid of the alias. Mind the ticks around the alias name - because if they were missing then the ZSH would expand them.

There is an alternative to stuffing all functions into one huge setup file: You can put each function into its own file, put them into some directories, point at these with $FPATH, and select their loading by means of autoload function .

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man zshmisc /AUTOLOADING FUNCTIONS

For each variable written in capital letters, eg PATH, there exists a variable by the same name in lowercase letters. If the upperase name is a list of items then the lowercase one contains these items separated by spaces.

[zsh] echo $PATH
/home/guckes/bin:/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games

[zsh] echo $path
/home/guckes/bin /usr/local/bin /usr/bin /bin /usr/bin/X11 /usr/games

This makes it a lot easier when dealing with such lists:

for dir in $path; do for> echo $dir for> done /home/guckes/bin /usr/local/bin /usr/bin /bin /usr/bin/X11 /usr/games

Note: When you are inside a "for" loop then the ZSH indicates this by indenting the input line with "for>".

And this makes assigning a value to a variable easier, too:

[zsh] path=( /home/guckes/bin /usr/local/bin /usr/bin /bin /usr/bin/X11 /usr/games )
[zsh] echo $PATH
/home/guckes/bin:/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games

[zsh] path=(
array> /home/guckes/bin
array> /usr/local/bin
array> /usr/bin
array> /bin
array> /usr/bin/X11
array> /usr/games
array> )

Again, ZSH helps to see the current context with showing a special input prompt, "array>".

You can now easily modify this input by going back to the command and move the cursor into the input, line by line, editing them, or even delete some:

path=(
/home/guckes/bin
/usr/local/bin
/usr/bin
/bin
)

ZLE - the ZSH Line Editor

The input line of shells can be long, and even be *very* long. But these are displayed as *one* long line which gets broken across several lines on screen. A long line simply gets unreadble, very much like program code which is presented in one long line.

The ZSH has a builtin line editor which allows editing across several lines on screen - but *with* EOLs, so it allows to split up the input line into several lines making editing and reading a lot easier for the user. You can move the cursor between the parts of the input line up and down.

See also: man zshzle

Editing Commands

The command insert-last-word inserts the last word from the previous command line. This easily reuses the word without having to type it in again yourself. Simply type 'ESC' followed by '_' (underscore)

[zsh] ls -l .newsrc.news-cis-dfn-de
[zsh] ln -s ESC_ .newsrc
[zsh] ln -s .newsrc.news-cis-dfn-de .newsrc

[zsh] bindkey | grep insert-last-word
"^[." insert-last-word
"^[_" insert-last-word

See also: man zshzle

print [TODO]

The print command is similar to "echo" - but allows to sort the input and set the output in columns.

Example: Print the list of letters on the keyboard in columns after they are sorted (option "-o").

[zsh] print -o -C 4  q w e r t y u i o p \
      a s d f g h j k l z x c v b n m
a  h  o  v
b  i  p  w
c  j  q  x
d  k  r  y
e  l  s  z
f  m  t
g  n  u

Note that the last row spells "gnu"! :-)

And if you'd liked to check up on the expandos for the prompt then you can use option "-P" for this without the need to change PS1 at all:

Co-Processes [TODO]

The ZSH supports co-processes (just like the ksh). This allows to

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typeset [TODO]

The typeset command is like "echo" - but a lot more powerful. It can align text, uppercase/lowercase it,

See also: man zshbuiltins , section "typeset"

Filename Expansion with Qualifiers

man zshexpn /Glob Qualifier

Qualifier "lowercase"

=() (NAME?)

mutt -f =(cat mail1 mail2 mail3 mail4) ruft mutt mit einer temporären Datei, die diese 4 Mailordner enthält, auf.
(mutt ist ein sehr schönes Mail-Programm, das ich empfehlen kann. Mit mutt -f liest mutt nicht aus /var/spool/mail, sondern die Email-Datei, hier mailfolder.gz)
Ein anderes Beispiel: lynxbzgrep() { lynx -force_html -dump =(bzip2 -cd $1) | grep $2) } ermöglicht es, mit lynxbz bzip2-gepackte HTML-Seiten nach einem Begriff zu untersuchen.

Noch viel besser: Statt einer temporären Datei kann man sogar einen Koprozess bequem aufrufen, indem man <() lynx -force_html <( gzip -cd komprimiert.html.gz ) ist kein Problem . Hier wird lynx, was keine komprimierten Dateien lesen kann, mit dem Output von gzip -cd komprimiert.html.gz , besser einer named pipe gespeißt, sehr cool!

Durch intelligente Kommunikation verschiedener Prozeße wird es möglich, daß man zwei Pseudodateien erzeugen und miteinander vergleichen kann: In Shellkreisen wird dies als "named pipe" bezeichnet, die die Zsh indirekt erzeugt.

NULLCMD

Nach Setzung von READNULLCMD=less läßt sich eine Datei mit < datei unter less angucken. Einfach ein < vor die Datei setzen.

Redirection of output to multiple files

Redirection of input from multiple files

Redirection to file as well as send on to pipe

Globbing with Recursion

Builtin Command "vared"

Builtin Command "dirs"

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zzz () {

    NAMED_DIRECTORY=$PWD:t; # der Name des jetzigen Verzeichnisses wird
        #       an NAMED_DIRECTORY ohne die Hierarchie übergeben.
        # :t steht für tail.
     eval $NAMED_DIRECTORY=$PWD; # es findet die Setzung eines named directory statt.
    cd ~$NAMED_DIRECTORY; # es wird in das named directory gesprungen.
          # ist mit dem bestehenden Verzeichnis identisch
        # aber der Name ist kürzer im Prompt.
}

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wohin () {
  dirs -v
  print -n "Wohin? "
  read WOHIN
  cd +${WOHIN:=0}
}

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The name ZSH derives from Zhong Shao, teaching assistant at Princeton university (now [2004] at Yale). Paul Falstad thought that his login name, "zsh", was a good name for a shell.

Paul released zsh 1.0 to alt.sources on December 16th 1990.

Matthias Kopfermann - matthi(at)infodrom.north.de http://www.infodrom.north.de/~matthi/

Matthias is the author of the original version of this text. He started writing it on 1997-10-17 - in German, title "die ZSH Liebhaber Seite". [and his last edit of that page apparently was on 2000-10-06.] "I first learned about the ZSH when I read the Linux Gazette. A user presented a very simple solution using the ZSH about the topic 'renaming von uppercase letters of DOS files to Linux'. And on a page which covered the differences of shells I learne that the author said that the ZSH can probably do more than the author knows about himself. This made me curious."

Sven Guckes - www.guckes.net

Sven translated this page on 2003-11-09 and 2003-11-22 (gray November days) into English.

Sven Wischnowsky - www.w9y.de

Author of the completion code (compctl and compsys) - and then some. "Mann, muss ich mal Zeit gehabt haben ;-)" (man -

Zhong Shao