zsh(1)

Keybindings

Change input mode:

bindkey -v              change to vi keymap
+bindkey -e              change to emacs keymap
+

Define key-mappings:

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
+

Access edit buffer in zle widget:

$BUFFER       # Entire edit buffer content
+$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
+

Parameter

Default value:

# default value
+echo ${foo:-defval}   # defval
+foo=bar
+echo ${foo:-defval}   # bar
+

Alternative value:

echo ${foo:+altval}   # ''
+foo=bar
+echo ${foo:+altval}   # altval
+

Check variable set, error if not set:

echo ${foo:?msg}      # print `msg` and return errno `1`
+foo=bar
+echo ${foo:?msg}      # bar
+

Sub-string ${var:offset:length}:

foo=abcdef
+echo ${foo:1:3}       # bcd
+

Trim prefix ${var#prefix}:

foo=bar.baz
+echo ${foo#bar}       # .baz
+

Trim suffix ${var%suffix}:

foo=bar.baz
+echo ${foo%.baz}      # bar
+

Substitute pattern ${var/pattern/replace}:

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
+

+
Note: prefix/suffix/pattern are expanded as pathnames.
+

Variables

# Variable with local scope
+local var=val
+
+# Read-only variable
+readonly var=bal
+

Indexed arrays:

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
+

Associative arrays:

typeset -A arr
+arr[x]='aa'
+arr[y]='bb'
+echo $arr[x]           # aa
+

Tied arrays:

typeset -T VEC vec=(1 2 3) '|'
+
+echo $vec              # 1 2 3
+echo $VEC              # 1|2|3
+

Unique arrays (set):

typeset -U vec=(1 2 3)
+
+echo $vec             # 1 2 3
+vec+=(1 2 4)
+echo $vec             # 1 2 3 4
+

Expansion Flags

Join array to string j:sep::

foo=(1 2 3 4)
+echo ${(j:-:)foo}     # 1-2-3-4
+echo ${(j:\n:)foo}    # join with new lines
+

Split string to array s:sep:

foo='1-2-3-4'
+bar=(${(s:-:)foo})    # capture as array
+echo $bar             # 1 2 3 4
+echo $bar[2]          # 2
+

Upper/Lower case string:

foo=aaBB
+echo ${(L)foo}        # aabb
+echo ${(U)foo}        # AABB
+

Key/values in associative arrays:

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
+

I/O redirections

See bash - I/O redirection

Process substitution

Process substitution allows to redirect the stdout of multiple processes at +once.

vim -d <(grep foo bar) <(grep foo moose)
+

Argument parsing with `zparseopts`

zparseopts [-D] [-E] [-A assoc] specs
+

Arguments are copied into the associative array assoc according to specs. +Each spec is described by an entry as opt[:][=array].

opt is the option without the - char. Passing -f is matched against f +opt, --long is matched against -long.
Using : means the option will take an argument.
The optional =array specifies an alternate storage container where this +option should be stored.

+
Documentation can be found in man zshmodules.
+

Example

#!/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
+

Regular Expressions

Zsh supports regular expression matching with the binary operator =~. +The match results can be accessed via the $MATCH variable and +$match indexed array:

$MATCH contains the full match
$match[1] contains match of the first capture group

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
+

Completion

Installation

Completion functions are provided via files and need to be placed in a location +covered by $fpath. By convention the completion files are names as _<CMD>.

A completion skeleton for the command foo, stored in _foo

#compdef _foo foo
+
+function _foo() {
+    ...
+}
+

Alternatively one can install a completion function explicitly by calling compdef <FUNC> <CMD>.

Completion Variables

Following variables are available in Completion functions:

$words              # array with command line in words
+$#words             # number words
+$CURRENT            # index into $words for cursor position
+$words[CURRENT-1]   # previous word (relative to cursor position)
+

Completion Functions

_describe simple completion, just words + description
_arguments sophisticated completion, allow to specify actions

Completion with `_describe`

_describe MSG COMP
+

MSG simple string with header message
COMP array of completions where each entry is "opt:description"

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
+

Completion with `_arguments`

_arguments SPEC [SPEC...]
+

where SPEC can have one of the following forms:

OPT[DESC]:MSG:ACTION for option flags
N:MSG:ACTION for positional arguments

Available actions

(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
+

Example

Skeleton to copy/paste for writing simple completions.

Assume a program foo with the following interface:

foo -c green|red|blue -s low|high -f <file> -d <dir> -h
+

The completion handler could be implemented as follows in a file called _foo:

#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
+}
+

Example with optional arguments

For this example we assume that the command foo takes at least three optional +arguments such as

foo arg1 arg2 arg3 [argN..]
+

function _foo() {
+    _arguments              \
+        "1:opt 1:(a b c)"   \
+        ":opt next:(d e f)" \
+        "*:opt all:(u v w)"
+}
+

Explanation:

1:MSG:ACTION sets completion for the first optional argument
:MSG:ACTION sets completion for the next optional argument
*:MSG:ACTION sets completion for the optional argument where none of the +previous rules apply, so in our example for arg3, argN...

+
_files is a zsh builtin utility function to complete files/dirs see
+
+
zsh completion functions
+
zsh completion utility functions
+
+

+ +

Notes