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                <ol class="chapter"><li class="chapter-item expanded affix "><a href="../intro.html">Introduction</a></li><li class="chapter-item expanded "><a href="../shells/index.html"><strong aria-hidden="true">1.</strong> Shells</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../shells/zsh.html" class="active"><strong aria-hidden="true">1.1.</strong> zsh</a></li><li class="chapter-item expanded "><a href="../shells/bash.html"><strong aria-hidden="true">1.2.</strong> bash</a></li><li class="chapter-item expanded "><a href="../shells/fish.html"><strong aria-hidden="true">1.3.</strong> fish</a></li></ol></li><li class="chapter-item expanded "><a href="../cli/index.html"><strong aria-hidden="true">2.</strong> CLI foo</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../cli/awk.html"><strong aria-hidden="true">2.1.</strong> awk</a></li><li class="chapter-item expanded "><a href="../cli/sed.html"><strong aria-hidden="true">2.2.</strong> sed</a></li><li class="chapter-item expanded "><a href="../cli/column.html"><strong aria-hidden="true">2.3.</strong> column</a></li><li class="chapter-item expanded "><a href="../cli/sort.html"><strong aria-hidden="true">2.4.</strong> sort</a></li><li class="chapter-item expanded "><a href="../cli/tr.html"><strong aria-hidden="true">2.5.</strong> tr</a></li><li class="chapter-item expanded "><a href="../cli/tac.html"><strong aria-hidden="true">2.6.</strong> tac</a></li><li class="chapter-item expanded "><a href="../cli/paste.html"><strong aria-hidden="true">2.7.</strong> paste</a></li></ol></li><li class="chapter-item expanded "><a href="../tools/index.html"><strong aria-hidden="true">3.</strong> Tools</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../tools/tmux.html"><strong aria-hidden="true">3.1.</strong> tmux</a></li><li class="chapter-item expanded "><a href="../tools/screen.html"><strong aria-hidden="true">3.2.</strong> screen</a></li><li class="chapter-item expanded "><a href="../tools/emacs.html"><strong aria-hidden="true">3.3.</strong> emacs</a></li><li class="chapter-item expanded "><a href="../tools/gpg.html"><strong aria-hidden="true">3.4.</strong> gpg</a></li><li class="chapter-item expanded "><a href="../tools/radare2.html"><strong aria-hidden="true">3.5.</strong> radare2</a></li><li class="chapter-item expanded "><a href="../tools/qemu.html"><strong aria-hidden="true">3.6.</strong> qemu</a></li><li class="chapter-item expanded "><a href="../tools/pacman.html"><strong aria-hidden="true">3.7.</strong> pacman</a></li><li class="chapter-item expanded "><a href="../tools/dot.html"><strong aria-hidden="true">3.8.</strong> dot</a></li><li class="chapter-item expanded "><a href="../tools/ffmpeg.html"><strong aria-hidden="true">3.9.</strong> ffmpeg</a></li><li class="chapter-item expanded "><a href="../tools/gnuplot.html"><strong aria-hidden="true">3.10.</strong> gnuplot</a></li><li class="chapter-item expanded "><a href="../tools/restic.html"><strong aria-hidden="true">3.11.</strong> restic</a></li><li class="chapter-item expanded "><a href="../tools/qrencode.html"><strong aria-hidden="true">3.12.</strong> qrencode</a></li></ol></li><li class="chapter-item expanded "><a href="../process/index.html"><strong aria-hidden="true">4.</strong> Process management & inspection</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../process/lsof.html"><strong aria-hidden="true">4.1.</strong> lsof</a></li><li class="chapter-item expanded "><a href="../process/pidstat.html"><strong aria-hidden="true">4.2.</strong> pidstat</a></li><li class="chapter-item expanded "><a href="../process/pgrep.html"><strong aria-hidden="true">4.3.</strong> pgrep</a></li><li class="chapter-item expanded "><a href="../process/ps.html"><strong aria-hidden="true">4.4.</strong> ps</a></li><li class="chapter-item expanded "><a href="../process/pmap.html"><strong aria-hidden="true">4.5.</strong> pmap</a></li><li class="chapter-item expanded "><a href="../process/pstack.html"><strong aria-hidden="true">4.6.</strong> pstack</a></li><li class="chapter-item expanded "><a href="../process/taskset.html"><strong aria-hidden="true">4.7.</strong> taskset</a></li><li class="chapter-item expanded "><a href="../process/nice.html"><strong aria-hidden="true">4.8.</strong> nice</a></li></ol></li><li class="chapter-item expanded "><a href="../trace_profile/index.html"><strong aria-hidden="true">5.</strong> Trace and Profile</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../trace_profile/time.html"><strong aria-hidden="true">5.1.</strong> time</a></li><li class="chapter-item expanded "><a href="../trace_profile/strace.html"><strong aria-hidden="true">5.2.</strong> strace</a></li><li class="chapter-item expanded "><a href="../trace_profile/ltrace.html"><strong aria-hidden="true">5.3.</strong> ltrace</a></li><li class="chapter-item expanded "><a href="../trace_profile/perf.html"><strong aria-hidden="true">5.4.</strong> perf</a></li><li class="chapter-item expanded "><a href="../trace_profile/oprofile.html"><strong aria-hidden="true">5.5.</strong> OProfile</a></li><li class="chapter-item expanded "><a href="../trace_profile/callgrind.html"><strong aria-hidden="true">5.6.</strong> callgrind</a></li><li class="chapter-item expanded "><a href="../trace_profile/valgrind.html"><strong aria-hidden="true">5.7.</strong> valgrind</a></li></ol></li><li class="chapter-item expanded "><a href="../debug/index.html"><strong aria-hidden="true">6.</strong> Debug</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../debug/gdb.html"><strong aria-hidden="true">6.1.</strong> gdb</a></li><li class="chapter-item expanded "><a href="../debug/gdbserver.html"><strong aria-hidden="true">6.2.</strong> gdbserver</a></li></ol></li><li class="chapter-item expanded "><a href="../binary/index.html"><strong aria-hidden="true">7.</strong> Binary</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../binary/od.html"><strong aria-hidden="true">7.1.</strong> od</a></li><li class="chapter-item expanded "><a href="../binary/xxd.html"><strong aria-hidden="true">7.2.</strong> xxd</a></li><li class="chapter-item expanded "><a href="../binary/readelf.html"><strong aria-hidden="true">7.3.</strong> readelf</a></li><li class="chapter-item expanded "><a href="../binary/objdump.html"><strong aria-hidden="true">7.4.</strong> objdump</a></li><li class="chapter-item expanded "><a href="../binary/nm.html"><strong aria-hidden="true">7.5.</strong> nm</a></li></ol></li><li class="chapter-item expanded "><a href="../development/index.html"><strong aria-hidden="true">8.</strong> Development</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../development/c++filt.html"><strong aria-hidden="true">8.1.</strong> c++filt</a></li><li class="chapter-item expanded "><a href="../development/c++.html"><strong aria-hidden="true">8.2.</strong> c++</a></li><li class="chapter-item expanded "><a href="../development/glibc.html"><strong aria-hidden="true">8.3.</strong> glibc</a></li><li class="chapter-item expanded "><a href="../development/gcc.html"><strong aria-hidden="true">8.4.</strong> gcc</a></li><li class="chapter-item expanded "><a href="../development/git.html"><strong aria-hidden="true">8.5.</strong> git</a></li><li class="chapter-item expanded "><a href="../development/cmake.html"><strong aria-hidden="true">8.6.</strong> cmake</a></li><li class="chapter-item expanded "><a href="../development/make.html"><strong aria-hidden="true">8.7.</strong> make</a></li><li class="chapter-item expanded "><a href="../development/ld.so.html"><strong aria-hidden="true">8.8.</strong> ld.so</a></li><li class="chapter-item expanded "><a href="../development/symbolver.html"><strong aria-hidden="true">8.9.</strong> symbol versioning</a></li><li class="chapter-item expanded "><a href="../development/python.html"><strong aria-hidden="true">8.10.</strong> python</a></li><li class="chapter-item expanded "><a href="../development/gcov.html"><strong aria-hidden="true">8.11.</strong> gcov</a></li><li class="chapter-item expanded "><a href="../development/pgo.html"><strong aria-hidden="true">8.12.</strong> pgo</a></li></ol></li><li class="chapter-item expanded "><a href="../linux/index.html"><strong aria-hidden="true">9.</strong> Linux</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../linux/systemd.html"><strong aria-hidden="true">9.1.</strong> systemd</a></li><li class="chapter-item expanded "><a href="../linux/coredump.html"><strong aria-hidden="true">9.2.</strong> coredump</a></li><li class="chapter-item expanded "><a href="../linux/ptrace_scope.html"><strong aria-hidden="true">9.3.</strong> ptrace_scope</a></li><li class="chapter-item expanded "><a href="../linux/cryptsetup.html"><strong aria-hidden="true">9.4.</strong> cryptsetup</a></li><li class="chapter-item expanded "><a href="../linux/swap.html"><strong aria-hidden="true">9.5.</strong> swap</a></li><li class="chapter-item expanded "><a href="../linux/input.html"><strong aria-hidden="true">9.6.</strong> input</a></li><li class="chapter-item expanded "><a href="../linux/acl.html"><strong aria-hidden="true">9.7.</strong> acl</a></li><li class="chapter-item expanded "><a href="../linux/zfs.html"><strong aria-hidden="true">9.8.</strong> zfs</a></li><li class="chapter-item expanded "><a href="../linux/cpufreq.html"><strong aria-hidden="true">9.9.</strong> cpufreq</a></li><li class="chapter-item expanded "><a href="../linux/cups.html"><strong aria-hidden="true">9.10.</strong> cups</a></li></ol></li><li class="chapter-item expanded "><a href="../network/index.html"><strong aria-hidden="true">10.</strong> Network</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../network/ssh.html"><strong aria-hidden="true">10.1.</strong> ssh</a></li><li class="chapter-item expanded "><a href="../network/ss.html"><strong aria-hidden="true">10.2.</strong> ss</a></li><li class="chapter-item expanded "><a href="../network/tcpdump.html"><strong aria-hidden="true">10.3.</strong> tcpdump</a></li><li class="chapter-item expanded "><a href="../network/tshark.html"><strong aria-hidden="true">10.4.</strong> tshark</a></li><li class="chapter-item expanded "><a href="../network/firewall-cmd.html"><strong aria-hidden="true">10.5.</strong> firewall-cmd</a></li><li class="chapter-item expanded "><a href="../network/nftables.html"><strong aria-hidden="true">10.6.</strong> nftables</a></li></ol></li><li class="chapter-item expanded "><a href="../web/index.html"><strong aria-hidden="true">11.</strong> Web</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../web/html.html"><strong aria-hidden="true">11.1.</strong> html</a></li><li class="chapter-item expanded "><a href="../web/css.html"><strong aria-hidden="true">11.2.</strong> css</a></li><li class="chapter-item expanded "><a href="../web/chartjs.html"><strong aria-hidden="true">11.3.</strong> chartjs</a></li><li class="chapter-item expanded "><a href="../web/plotly.html"><strong aria-hidden="true">11.4.</strong> plotly</a></li></ol></li><li class="chapter-item expanded "><a href="../arch/index.html"><strong aria-hidden="true">12.</strong> Arch</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../arch/x86_64.html"><strong aria-hidden="true">12.1.</strong> x86_64</a></li><li class="chapter-item expanded "><a href="../arch/armv8.html"><strong aria-hidden="true">12.2.</strong> armv8</a></li><li class="chapter-item expanded "><a href="../arch/arm64.html"><strong aria-hidden="true">12.3.</strong> arm64</a></li><li class="chapter-item expanded "><a href="../arch/armv7.html"><strong aria-hidden="true">12.4.</strong> armv7</a></li><li class="chapter-item expanded "><a href="../arch/riscv.html"><strong aria-hidden="true">12.5.</strong> riscv</a></li></ol></li></ol>
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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 &lt;key&gt;             dump &lt;key&gt; 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 &lt;(grep foo bar) &lt;(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 "&lt;CMDs&gt;" &lt;SIG&gt;/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 &amp;&amp; echo "run exit trap"' EXIT

# -&gt; no print
exit 0
# -&gt; 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&gt;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>_&lt;CMD&gt;</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 &lt;FUNC&gt; &lt;CMD&gt;</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 &lt;TAB&gt;&lt;TAB&gt;
 -- 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
-&gt;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 &lt;file&gt; -d &lt;dir&gt; -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:-&gt;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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                <ol class="chapter"><li class="chapter-item expanded affix "><a href="../intro.html">Introduction</a></li><li class="chapter-item expanded "><a href="../shells/index.html"><strong aria-hidden="true">1.</strong> Shells</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../shells/zsh.html" class="active"><strong aria-hidden="true">1.1.</strong> zsh</a></li><li class="chapter-item expanded "><a href="../shells/bash.html"><strong aria-hidden="true">1.2.</strong> bash</a></li><li class="chapter-item expanded "><a href="../shells/fish.html"><strong aria-hidden="true">1.3.</strong> fish</a></li></ol></li><li class="chapter-item expanded "><a href="../cli/index.html"><strong aria-hidden="true">2.</strong> CLI foo</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../cli/awk.html"><strong aria-hidden="true">2.1.</strong> awk</a></li><li class="chapter-item expanded "><a href="../cli/sed.html"><strong aria-hidden="true">2.2.</strong> sed</a></li><li class="chapter-item expanded "><a href="../cli/column.html"><strong aria-hidden="true">2.3.</strong> column</a></li><li class="chapter-item expanded "><a href="../cli/sort.html"><strong aria-hidden="true">2.4.</strong> sort</a></li><li class="chapter-item expanded "><a href="../cli/tr.html"><strong aria-hidden="true">2.5.</strong> tr</a></li><li class="chapter-item expanded "><a href="../cli/tac.html"><strong aria-hidden="true">2.6.</strong> tac</a></li><li class="chapter-item expanded "><a href="../cli/paste.html"><strong aria-hidden="true">2.7.</strong> paste</a></li></ol></li><li class="chapter-item expanded "><a href="../tools/index.html"><strong aria-hidden="true">3.</strong> Tools</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../tools/tmux.html"><strong aria-hidden="true">3.1.</strong> tmux</a></li><li class="chapter-item expanded "><a href="../tools/screen.html"><strong aria-hidden="true">3.2.</strong> screen</a></li><li class="chapter-item expanded "><a href="../tools/emacs.html"><strong aria-hidden="true">3.3.</strong> emacs</a></li><li class="chapter-item expanded "><a href="../tools/gpg.html"><strong aria-hidden="true">3.4.</strong> gpg</a></li><li class="chapter-item expanded "><a href="../tools/radare2.html"><strong aria-hidden="true">3.5.</strong> radare2</a></li><li class="chapter-item expanded "><a href="../tools/qemu.html"><strong aria-hidden="true">3.6.</strong> qemu</a></li><li class="chapter-item expanded "><a href="../tools/pacman.html"><strong aria-hidden="true">3.7.</strong> pacman</a></li><li class="chapter-item expanded "><a href="../tools/dot.html"><strong aria-hidden="true">3.8.</strong> dot</a></li><li class="chapter-item expanded "><a href="../tools/ffmpeg.html"><strong aria-hidden="true">3.9.</strong> ffmpeg</a></li><li class="chapter-item expanded "><a href="../tools/gnuplot.html"><strong aria-hidden="true">3.10.</strong> gnuplot</a></li><li class="chapter-item expanded "><a href="../tools/restic.html"><strong aria-hidden="true">3.11.</strong> restic</a></li><li class="chapter-item expanded "><a href="../tools/qrencode.html"><strong aria-hidden="true">3.12.</strong> qrencode</a></li></ol></li><li class="chapter-item expanded "><a href="../process/index.html"><strong aria-hidden="true">4.</strong> Process management & inspection</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../process/lsof.html"><strong aria-hidden="true">4.1.</strong> lsof</a></li><li class="chapter-item expanded "><a href="../process/pidstat.html"><strong aria-hidden="true">4.2.</strong> pidstat</a></li><li class="chapter-item expanded "><a href="../process/pgrep.html"><strong aria-hidden="true">4.3.</strong> pgrep</a></li><li class="chapter-item expanded "><a href="../process/ps.html"><strong aria-hidden="true">4.4.</strong> ps</a></li><li class="chapter-item expanded "><a href="../process/pmap.html"><strong aria-hidden="true">4.5.</strong> pmap</a></li><li class="chapter-item expanded "><a href="../process/pstack.html"><strong aria-hidden="true">4.6.</strong> pstack</a></li><li class="chapter-item expanded "><a href="../process/taskset.html"><strong aria-hidden="true">4.7.</strong> taskset</a></li><li class="chapter-item expanded "><a href="../process/nice.html"><strong aria-hidden="true">4.8.</strong> nice</a></li></ol></li><li class="chapter-item expanded "><a href="../trace_profile/index.html"><strong aria-hidden="true">5.</strong> Trace and Profile</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../trace_profile/time.html"><strong aria-hidden="true">5.1.</strong> time</a></li><li class="chapter-item expanded "><a href="../trace_profile/strace.html"><strong aria-hidden="true">5.2.</strong> strace</a></li><li class="chapter-item expanded "><a href="../trace_profile/ltrace.html"><strong aria-hidden="true">5.3.</strong> ltrace</a></li><li class="chapter-item expanded "><a href="../trace_profile/perf.html"><strong aria-hidden="true">5.4.</strong> perf</a></li><li class="chapter-item expanded "><a href="../trace_profile/oprofile.html"><strong aria-hidden="true">5.5.</strong> OProfile</a></li><li class="chapter-item expanded "><a href="../trace_profile/callgrind.html"><strong aria-hidden="true">5.6.</strong> callgrind</a></li><li class="chapter-item expanded "><a href="../trace_profile/valgrind.html"><strong aria-hidden="true">5.7.</strong> valgrind</a></li></ol></li><li class="chapter-item expanded "><a href="../debug/index.html"><strong aria-hidden="true">6.</strong> Debug</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../debug/gdb.html"><strong aria-hidden="true">6.1.</strong> gdb</a></li><li class="chapter-item expanded "><a href="../debug/gdbserver.html"><strong aria-hidden="true">6.2.</strong> gdbserver</a></li></ol></li><li class="chapter-item expanded "><a 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versioning</a></li><li class="chapter-item expanded "><a href="../development/python.html"><strong aria-hidden="true">8.10.</strong> python</a></li><li class="chapter-item expanded "><a href="../development/gcov.html"><strong aria-hidden="true">8.11.</strong> gcov</a></li><li class="chapter-item expanded "><a href="../development/pgo.html"><strong aria-hidden="true">8.12.</strong> pgo</a></li></ol></li><li class="chapter-item expanded "><a href="../linux/index.html"><strong aria-hidden="true">9.</strong> Linux</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../linux/systemd.html"><strong aria-hidden="true">9.1.</strong> systemd</a></li><li class="chapter-item expanded "><a href="../linux/coredump.html"><strong aria-hidden="true">9.2.</strong> coredump</a></li><li class="chapter-item expanded "><a href="../linux/ptrace_scope.html"><strong aria-hidden="true">9.3.</strong> ptrace_scope</a></li><li class="chapter-item expanded "><a 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href="../network/ssh.html"><strong aria-hidden="true">10.1.</strong> ssh</a></li><li class="chapter-item expanded "><a href="../network/ss.html"><strong aria-hidden="true">10.2.</strong> ss</a></li><li class="chapter-item expanded "><a href="../network/tcpdump.html"><strong aria-hidden="true">10.3.</strong> tcpdump</a></li><li class="chapter-item expanded "><a href="../network/tshark.html"><strong aria-hidden="true">10.4.</strong> tshark</a></li><li class="chapter-item expanded "><a href="../network/firewall-cmd.html"><strong aria-hidden="true">10.5.</strong> firewall-cmd</a></li><li class="chapter-item expanded "><a href="../network/nftables.html"><strong aria-hidden="true">10.6.</strong> nftables</a></li></ol></li><li class="chapter-item expanded "><a href="../web/index.html"><strong aria-hidden="true">11.</strong> Web</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../web/html.html"><strong aria-hidden="true">11.1.</strong> html</a></li><li class="chapter-item expanded "><a href="../web/css.html"><strong aria-hidden="true">11.2.</strong> css</a></li><li class="chapter-item expanded "><a href="../web/chartjs.html"><strong aria-hidden="true">11.3.</strong> chartjs</a></li><li class="chapter-item expanded "><a href="../web/plotly.html"><strong aria-hidden="true">11.4.</strong> plotly</a></li></ol></li><li class="chapter-item expanded "><a href="../arch/index.html"><strong aria-hidden="true">12.</strong> Arch</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../arch/x86_64.html"><strong aria-hidden="true">12.1.</strong> x86_64</a></li><li class="chapter-item expanded "><a href="../arch/armv8.html"><strong aria-hidden="true">12.2.</strong> armv8</a></li><li class="chapter-item expanded "><a href="../arch/arm64.html"><strong aria-hidden="true">12.3.</strong> arm64</a></li><li class="chapter-item expanded "><a href="../arch/armv7.html"><strong aria-hidden="true">12.4.</strong> armv7</a></li><li class="chapter-item expanded "><a href="../arch/riscv.html"><strong aria-hidden="true">12.5.</strong> riscv</a></li></ol></li></ol>
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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 &lt;key&gt;             dump &lt;key&gt; 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 &lt;(grep foo bar) &lt;(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 "&lt;CMDs&gt;" &lt;SIG&gt;/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 &amp;&amp; echo "run exit trap"' EXIT

# -&gt; no print
exit 0
# -&gt; 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&gt;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>_&lt;CMD&gt;</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 &lt;FUNC&gt; &lt;CMD&gt;</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 &lt;TAB&gt;&lt;TAB&gt;
 -- 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
-&gt;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 &lt;file&gt; -d &lt;dir&gt; -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:-&gt;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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