Zsh Scripting Cheat Sheet

arr=(one two three)echo $arr[1]          # "one"  (1-indexed, unlike bash's 0-index)echo ${arr[1]}        # same, braces optional for simple indexecho ${#arr}          # 3, length of arrayecho ${arr[-1]}       # "three", negative indices work# Slicingecho ${arr[1,2]}      # "one two"# Append / iteratearr+=(four)for item in $arr; do  echo "$item"done# Associative arraystypeset -A colorscolors=(red "#f00" green "#0f0")echo $colors[red]     # "#f00"

setopt extendedglobls *.txt~backup.txt     # all .txt except backup.txtls **/*.py               # recursive glob, any depthls *(.)                  # only regular files in cwdls *(/)                  # only directoriesls *(.om[1])             # most recently modified regular filels *.log(.N)              # .N suppresses "no match" error instead of failing# Qualifiers: (.)=file (/)=dir (@)=symlink (x)=executable# (Lxx)=size, (mxx)=modified within xx days

name=""echo ${name:-default}     # use "default" if name is unset or emptyecho ${name:=default}     # same, and also assigns name=defaultpath="/usr/local/bin/zsh"echo ${path:h}             # "/usr/local/bin" (head, like dirname)echo ${path:t}              # "zsh" (tail, like basename)echo ${path:e}               # "" (extension)echo ${path:r}                # "/usr/local/bin/zsh" (root, strip extension)str="Hello World"echo ${(L)str}     # "hello world" lowercaseecho ${(U)str}     # "HELLO WORLD" uppercaseecho ${(C)str}     # "Hello World" capitalize each word# Splitting a string into an arraywords=(${(s: :)"a b c"})

greet() {  local name=${1:-world}  print "Hello, $name"}# Autoloaded functions (in fpath, loaded lazily)autoload -Uz compinit && compinitautoload -Uz colors && colors# PROMPT uses %-escapes instead of bash's \-escapesPROMPT='%F{cyan}%n@%m%f %~ %# '# %n=user %m=host %~=cwd(with ~) %#=# if root else %# Hooksprecmd() { print "runs before each prompt" }

#compdef mytool_mytool() {  local -a subcmds  subcmds=(    'build:compile the project'    'test:run the test suite'    'deploy:ship to production'  )  _arguments -C \    '1:command:->cmds' \    '*::arg:->args'  case $state in    cmds) _describe 'command' subcmds ;;    args)      case $words[1] in        deploy) _arguments '--env=[target environment]:env:(staging prod)' ;;      esac      ;;  esac}compdef _mytool mytool# Quick inline completion without a full functioncompdef '_files -g "*.log"' tailog

TRAPINT() {  print "Caught Ctrl-C, cleaning up..."  return 130   # non-zero return from TRAPINT still lets the script exit}TRAPEXIT() {  print "Always runs, like a shell-wide 'finally'"}# Fail fast, similar to bash's set -e, but with finer-grained controlsetopt ERR_EXIT        # exit on any unhandled non-zero statussetopt PIPE_FAIL         # a pipeline fails if any stage fails, not just the lastsetopt ERR_RETURN          # inside a function, return instead of exiting the shell# Explicit per-command error handling without relying on ERR_EXITsome_cmd || { print "some_cmd failed: $?" >&2; exit 1 }

# Process substitution: treat command output as a filediff <(sort file1.txt) <(sort file2.txt)comm -12 <(sort a.txt) <(sort b.txt)# Tee into multiple process substitutions at oncetee >(gzip > out.gz) >(wc -l) < input.txt > /dev/null# Coprocesses: a background process with a two-way pipecoproc mycalc { bc -l }print -p "2 + 2"            # write to the coprocess's stdinread -p result                # read from the coprocess's stdoutprint $result                   # "4"# Job controllong_task &                       # background jobjobs -l                             # list jobs with PIDsfg %1                                 # bring job 1 to foregrounddisown %1                               # detach job (survives shell exit)wait %1                                   # block until job 1 finishes

zmodload zsh/mathfuncprint $(( sqrt(2) ))            # 1.4142135623730951print $(( sin(3.14159/2) ))       # ~1# Arithmetic context supports C-style ternaries(( x = 5 > 3 ? 10 : 20 ))print $x                            # 10# typeset -T ties a scalar and an array together (colon-split, like PATH)typeset -T MY_PATH my_path ':'my_path=(/usr/bin /usr/local/bin)print $MY_PATH                        # "/usr/bin:/usr/local/bin"MY_PATH="/opt/bin:/opt/sbin"print $my_path[1]                       # "/opt/bin", array stays in sync# Fixed-width float and integer typingtypeset -F 3 pi=3.14159265               # float, printed with 3 decimalstypeset -i base16 hex=16#ff                # integer with a fixed output baseprint $hex                                   # 255