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<h1 id="zsh1"><a class="header" href="#zsh1">zsh(1)</a></h1>
<h2 id="keybindings"><a class="header" href="#keybindings">Keybindings</a></h2>
<p>Change input mode:</p>
<pre><code class="language-zsh">bindkey -v change to vi keymap
bindkey -e change to emacs keymap
</code></pre>
<p>Define key-mappings:</p>
<pre><code class="language-zsh">bindkey list mappings in current keymap
bindkey in-str cmd create mapping for `in-str` to `cmd`
bindkey -r in-str remove binding for `in-str`
# C-v <key> dump <key> code, which can be used in `in-str`
# zle -l list all functions for keybindings
# man zshzle(1) STANDARD WIDGETS: get description of functions
</code></pre>
<p>Access edit buffer in zle widget:</p>
<pre><code class="language-zsh">$BUFFER # Entire edit buffer content
$LBUFFER # Edit buffer content left to cursor
$RBUFFER # Edit buffer content right to cursor
# create zle widget which adds text right of the cursor
function add-text() {
RBUFFER="some text $RBUFFER"
}
zle -N add-text
bindkey "^p" add-text
</code></pre>
<h2 id="parameter"><a class="header" href="#parameter">Parameter</a></h2>
<p>Default value:</p>
<pre><code class="language-zsh"># default value
echo ${foo:-defval} # defval
foo=bar
echo ${foo:-defval} # bar
</code></pre>
<p>Alternative value:</p>
<pre><code class="language-zsh">echo ${foo:+altval} # ''
foo=bar
echo ${foo:+altval} # altval
</code></pre>
<p>Check variable set, error if not set:</p>
<pre><code class="language-zsh">echo ${foo:?msg} # print `msg` and return errno `1`
foo=bar
echo ${foo:?msg} # bar
</code></pre>
<p>Sub-string <code>${var:offset:length}</code>:</p>
<pre><code class="language-zsh">foo=abcdef
echo ${foo:1:3} # bcd
</code></pre>
<p>Trim prefix <code>${var#prefix}</code>:</p>
<pre><code class="language-zsh">foo=bar.baz
echo ${foo#bar} # .baz
</code></pre>
<p>Trim suffix <code>${var%suffix}</code>:</p>
<pre><code class="language-zsh">foo=bar.baz
echo ${foo%.baz} # bar
</code></pre>
<p>Substitute pattern <code>${var/pattern/replace}</code>:</p>
<pre><code class="language-zsh">foo=aabbccbbdd
echo ${foo/bb/XX} # aaXXccbbdd
echo ${foo//bb/XX} # aaXXccXXdd
# replace prefix
echo ${foo/#bb/XX} # aabbccbbdd
echo ${foo/#aa/XX} # XXbbccbbdd
# replace suffix
echo ${foo/%bb/XX} # aabbccbbdd
echo ${foo/%dd/XX} # aabbccbbXX
</code></pre>
<blockquote>
<p>Note: <code>prefix</code>/<code>suffix</code>/<code>pattern</code> are expanded as pathnames.</p>
</blockquote>
<h2 id="variables"><a class="header" href="#variables">Variables</a></h2>
<pre><code class="language-zsh"># Variable with local scope
local var=val
# Read-only variable
readonly var=bal
</code></pre>
<p>Indexed arrays:</p>
<pre><code class="language-zsh">arr=(aa bb cc dd)
echo $arr[1] # aa
echo $arr[-1] # dd
arr+=(ee)
echo $arr[-1] # ee
echo $arr[1,3] # aa bb cc
</code></pre>
<p>Associative arrays:</p>
<pre><code class="language-zsh">typeset -A arr
arr[x]='aa'
arr[y]='bb'
echo $arr[x] # aa
</code></pre>
<p>Tied arrays:</p>
<pre><code class="language-zsh">typeset -T VEC vec=(1 2 3) '|'
echo $vec # 1 2 3
echo $VEC # 1|2|3
</code></pre>
<p>Unique arrays (set):</p>
<pre><code>typeset -U vec=(1 2 3)
echo $vec # 1 2 3
vec+=(1 2 4)
echo $vec # 1 2 3 4
</code></pre>
<h3 id="expansion-flags"><a class="header" href="#expansion-flags">Expansion Flags</a></h3>
<p>Join array to string <code>j:sep:</code>:</p>
<pre><code class="language-zsh">foo=(1 2 3 4)
echo ${(j:-:)foo} # 1-2-3-4
echo ${(j:\n:)foo} # join with new lines
</code></pre>
<p>Split string to array <code>s:sep</code>:</p>
<pre><code class="language-zsh">foo='1-2-3-4'
bar=(${(s:-:)foo}) # capture as array
echo $bar # 1 2 3 4
echo $bar[2] # 2
</code></pre>
<p>Upper/Lower case string:</p>
<pre><code class="language-zsh">foo=aaBB
echo ${(L)foo} # aabb
echo ${(U)foo} # AABB
</code></pre>
<p>Key/values in associative arrays:</p>
<pre><code class="language-zsh">typeset -A vec; vec[a]='aa'; vec[b]='bb'
echo ${(k)vec} # a b
echo ${(v)vec} # aa bb
echo ${(kv)vec} # a aa b bb
# Iterate over key value pairs.
for k v in ${(kv)vec)}; do ...; done
</code></pre>
<h2 id="io-redirections"><a class="header" href="#io-redirections">I/O redirections</a></h2>
<p>See <a href="bash.html#io-redirection">bash - I/O redirection</a></p>
<h2 id="process-substitution"><a class="header" href="#process-substitution">Process substitution</a></h2>
<p>Process substitution allows to redirect the stdout of multiple processes at
once.</p>
<pre><code class="language-bash">vim -d <(grep foo bar) <(grep foo moose)
</code></pre>
<h2 id="argument-parsing-with-zparseopts"><a class="header" href="#argument-parsing-with-zparseopts">Argument parsing with <code>zparseopts</code></a></h2>
<pre><code class="language-zsh">zparseopts [-D] [-E] [-A assoc] specs
</code></pre>
<p>Arguments are copied into the associative array <code>assoc</code> according to <code>specs</code>.
Each spec is described by an entry as <code>opt[:][=array]</code>.</p>
<ul>
<li><code>opt</code> is the option without the <code>-</code> char. Passing <code>-f</code> is matched against <code>f</code>
opt, <code>--long</code> is matched against <code>-long</code>.</li>
<li>Using <code>:</code> means the option will take an argument.</li>
<li>The optional <code>=array</code> specifies an alternate storage container where this
option should be stored.</li>
</ul>
<blockquote>
<p>Documentation can be found in <code>man zshmodules</code>.</p>
</blockquote>
<h3 id="example"><a class="header" href="#example">Example</a></h3>
<pre><code class="language-zsh">#!/bin/zsh
function test() {
zparseopts -D -E -A opts f=flag o: -long:
echo "flag $flag"
echo "o $opts[-o]"
echo "long $opts[--long]"
echo "pos $1"
}
test -f -o OPTION --long LONG_OPT POSITIONAL
# Outputs:
# flag -f
# o OPTION
# long LONG_OPT
# pos POSITIONAL
</code></pre>
<h2 id="regular-expressions"><a class="header" href="#regular-expressions">Regular Expressions</a></h2>
<p>Zsh supports regular expression matching with the binary operator <code>=~</code>.
The match results can be accessed via the <code>$MATCH</code> variable and
<code>$match</code> indexed array:</p>
<ul>
<li><code>$MATCH</code> contains the full match</li>
<li><code>$match[1]</code> contains match of the first capture group</li>
</ul>
<pre><code class="language-zsh">INPUT='title foo : 1234'
REGEX='^title (.+) : ([0-9]+)$'
if [[ $INPUT =~ $REGEX ]]; then
echo "$MATCH" # title foo : 1234
echo "$match[1]" # foo
echo "$match[2]" # 1234
fi
</code></pre>
<h2 id="trap-handling"><a class="header" href="#trap-handling">Trap Handling</a></h2>
<pre><code class="language-zsh">trap "<CMDs>" <SIG>/EXIT
# Show current trap handler.
trap -p
# List signal names.
trap -l
</code></pre>
<h4 id="example-run-handler-only-on-error-exit"><a class="header" href="#example-run-handler-only-on-error-exit">Example: Run handler only on error exit</a></h4>
<pre><code class="language-zsh">trap 'test $? -ne 0 && echo "run exit trap"' EXIT
# -> no print
exit 0
# -> print
exit 1
</code></pre>
<h4 id="example-mutex-in-shell-script"><a class="header" href="#example-mutex-in-shell-script">Example: Mutex in shell script</a></h4>
<p>For example if a script is triggered in unsynchronized, we may want to ensure
that a single script instance runs.</p>
<pre><code class="language-zsh"># open file=LOCK with fd=100
exec 100>LOCK
# take exclusive lock, wait maximal for 3600s
flock -w 3600 -x 100 || { echo "flock timeout"; exit 1; }
# eg automatically release lock when script exits
trap "flock -u 100" EXIT
</code></pre>
<h2 id="completion"><a class="header" href="#completion">Completion</a></h2>
<h3 id="installation"><a class="header" href="#installation">Installation</a></h3>
<p>Completion functions are provided via files and need to be placed in a location
covered by <code>$fpath</code>. By convention the completion files are names as <code>_<CMD></code>.</p>
<p>A completion skeleton for the command <code>foo</code>, stored in <code>_foo</code></p>
<pre><code class="language-zsh">#compdef _foo foo
function _foo() {
...
}
</code></pre>
<p>Alternatively one can install a completion function explicitly by calling <code>compdef <FUNC> <CMD></code>.</p>
<h3 id="completion-variables"><a class="header" href="#completion-variables">Completion Variables</a></h3>
<p>Following variables are available in Completion functions:</p>
<pre><code class="language-zsh">$words # array with command line in words
$#words # number words
$CURRENT # index into $words for cursor position
$words[CURRENT-1] # previous word (relative to cursor position)
</code></pre>
<h3 id="completion-functions"><a class="header" href="#completion-functions">Completion Functions</a></h3>
<ul>
<li><code>_describe</code> simple completion, just words + description</li>
<li><code>_arguments</code> sophisticated completion, allow to specify actions</li>
</ul>
<h4 id="completion-with-_describe"><a class="header" href="#completion-with-_describe">Completion with <a href="http://zsh.sourceforge.net/Doc/Release/Completion-System.html#Completion-Functions"><code>_describe</code></a></a></h4>
<pre><code class="language-zsh">_describe MSG COMP
</code></pre>
<ul>
<li><code>MSG</code> simple string with header message</li>
<li><code>COMP</code> array of completions where each entry is <code>"opt:description"</code></li>
</ul>
<pre><code class="language-zsh">function _foo() {
local -a opts
opts=('bla:desc for bla' 'blu:desc for blu')
_describe 'foo-msg' opts
}
compdef _foo foo
foo <TAB><TAB>
-- foo-msg --
bla -- desc for bla
blu -- desc for blu
</code></pre>
<h4 id="completion-with-_arguments"><a class="header" href="#completion-with-_arguments">Completion with <a href="http://zsh.sourceforge.net/Doc/Release/Completion-System.html#Completion-Functions"><code>_arguments</code></a></a></h4>
<pre><code class="language-zsh">_arguments SPEC [SPEC...]
</code></pre>
<p>where <code>SPEC</code> can have one of the following forms:</p>
<ul>
<li><code>OPT[DESC]:MSG:ACTION</code> for option flags</li>
<li><code>N:MSG:ACTION</code> for positional arguments</li>
</ul>
<p>Available actions</p>
<pre><code class="language-zsh">(op1 op2) list possible matches
->VAL set $state=VAL and continue, `$state` can be checked later in switch case
FUNC call func to generate matches
{STR} evaluate `STR` to generate matches
</code></pre>
<h3 id="example-1"><a class="header" href="#example-1">Example</a></h3>
<p>Skeleton to copy/paste for writing simple completions.</p>
<p>Assume a program <code>foo</code> with the following interface:</p>
<pre><code class="language-zsh">foo -c green|red|blue -s low|high -f <file> -d <dir> -h
</code></pre>
<p>The completion handler could be implemented as follows in a file called <code>_foo</code>:</p>
<pre><code class="language-zsh">#compdef _foo foo
function _foo_color() {
local colors=()
colors+=('green:green color')
colors+=('red:red color')
colors+=('blue:blue color')
_describe "color" colors
}
function _foo() {
_arguments \
"-c[define color]:color:->s_color" \
"-s[select sound]:sound:(low high)" \
"-f[select file]:file:_files" \
"-d[select dir]:dir:_files -/" \
"-h[help]"
case $state in
s_color) _foo_color;;
esac
}
</code></pre>
<h3 id="example-with-optional-arguments"><a class="header" href="#example-with-optional-arguments">Example with optional arguments</a></h3>
<p>For this example we assume that the command <code>foo</code> takes at least three optional
arguments such as</p>
<pre><code class="language-zsh">foo arg1 arg2 arg3 [argN..]
</code></pre>
<pre><code class="language-zsh">function _foo() {
_arguments \
"1:opt 1:(a b c)" \
":opt next:(d e f)" \
"*:opt all:(u v w)"
}
</code></pre>
<p>Explanation:</p>
<ul>
<li><code>1:MSG:ACTION</code> sets completion for the <strong>first</strong> optional argument</li>
<li><code>:MSG:ACTION</code> sets completion for the <strong>next</strong> optional argument</li>
<li><code>*:MSG:ACTION</code> sets completion for the optional argument where none of the
previous rules apply, so in our example for <code>arg3, argN..</code>.</li>
</ul>
<blockquote>
<p><code>_files</code> is a zsh builtin utility function to complete files/dirs see</p>
<ul>
<li><a href="http://zsh.sourceforge.net/Doc/Release/Completion-System.html#Completion-Functions">zsh completion functions</a></li>
<li><a href="https://github.com/zsh-users/zsh-completions/blob/master/zsh-completions-howto.org#utility-functions">zsh completion utility functions</a></li>
</ul>
</blockquote>
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