Why is zsh the default shell on Mac?

Apple switched the default from bash to zsh in macOS Catalina (2019) because the bash it shipped was stuck at version 3.2 from 2007; newer bash releases moved to the GPLv3 license, which Apple avoids. zsh is under a permissive license, so Apple can ship a current version. For interactive use zsh does everything bash 3.2 did and more. If you prefer bash anyway, run chsh -s /bin/bash, but note that scripts starting with #!/bin/bash still run in bash either way; the default shell only affects your interactive terminal.

How do I fix zsh: command not found?

The command is either not installed or not on your PATH. Run echo $PATH and check whether the directory holding the binary is listed. If not, add export PATH="/path/to/dir:$PATH" to ~/.zshrc and run source ~/.zshrc. On an Apple Silicon Mac, Homebrew installs to /opt/homebrew, which is not on the default PATH, so command not found: brew (and everything brew installed) is fixed by adding eval "$(/opt/homebrew/bin/brew shellenv)" to ~/.zprofile. If you just installed the tool in this session, run rehash so zsh notices the new binary. Tools like nvm are shell functions, not binaries: their installer appends init lines to your shell config, and those lines must live in ~/.zshrc, not a leftover ~/.bash_profile.

How do I make an alias permanent in zsh?

An alias typed at the prompt dies with the session. Put the line in ~/.zshrc, which zsh reads at the start of every interactive session: echo "alias ll='ls -lah'" >> ~/.zshrc, then source ~/.zshrc to load it now. Quote the definition so the shell does not expand it while you are writing it. If the alias does not survive a new terminal, check you edited ~/.zshrc and not ~/.bashrc, a common leftover habit after switching from bash, and check that nothing later in the file redefines or unaliases it.

What is the difference between .zshrc and .zprofile?

~/.zprofile runs once per login shell, ~/.zshrc runs for every interactive shell. Put environment setup that should run once, like PATH exports and eval "$(brew shellenv)", in ~/.zprofile; put aliases, functions, keybindings, completion setup, and prompt config in ~/.zshrc. On macOS every new terminal tab is a login shell, so both files run and the split is mostly about tidiness. On Linux, terminal windows are usually interactive non-login shells, so only ~/.zshrc runs; anything only in ~/.zprofile will be missing until you log in fresh. ~/.zshenv runs for every zsh instance including scripts, so keep it minimal.

Do bash commands work in zsh?

Day to day, yes: the commands you type (ls, grep, ssh, git) are programs, not part of the shell, and pipes, redirection, &&, and $(command) all work the same. The differences bite in scripting and edge cases: zsh does not word-split unquoted variables, its arrays start at 1, and an unmatched glob is an error instead of being passed through. Bash scripts with a #!/bin/bash shebang keep running in bash regardless of your login shell, so nothing breaks there. What does not carry over automatically is your config: aliases and PATH lines in ~/.bashrc or ~/.bash_profile must be moved to ~/.zshrc.

zsh Cheat Sheet: Commands, Aliases & Oh My Zsh (2026)

History Search

Command	What it does
	Search history as you type (press again for older matches)
	Show the last 16 commands
	Show the whole history
	Search history for a command
	Rerun the last command ( reruns it as root)
	Last argument of the previous command
	All arguments of the previous command
	Rerun the most recent command starting with ssh
	Rerun history entry 42
	Insert the previous command's last argument (repeat to go older)
after typing	Only steps through matching commands if you bind prefix search (below)

History size and behaviour go in :

HISTSIZE=50000
SAVEHIST=50000
setopt SHARE_HISTORY          # share history across open terminals
setopt HIST_IGNORE_ALL_DUPS   # keep one copy of a repeated command
setopt HIST_IGNORE_SPACE      # commands starting with a space are not saved

# Up/Down search commands starting with what you typed
bindkey '^[[A' history-beginning-search-backward
bindkey '^[[B' history-beginning-search-forward

Keyboard Shortcuts

Emacs-style bindings, the default. See the next section for vi mode.

Key	Action
/	Start / end of line
/	Forward / back one word
	Delete the word before the cursor
	Delete the whole line
	Delete from cursor to end of line
	Paste what Ctrl+W/U/K deleted
	Clear the screen
	Cancel the current line or interrupt the running command
	Log out on an empty line; delete char otherwise
	Suspend the foreground job ( resumes)
	Complete; press again to cycle candidates
	Edit the current line in $EDITOR (after )

Aliases

Command	What it does
	Define an alias for this session
	List every defined alias
	Show one alias's definition
	Remove an alias
	Run the real command, ignoring the alias ( also works)
	Global alias, expands anywhere in the line:
	Suffix alias: typing opens it in less
	Typing opens it in VS Code

Aliases live for one session unless you put them in :

echo "alias ll='ls -lah'" >> ~/.zshrc
source ~/.zshrc

Completion

zsh's completion system knows flags, hostnames, git branches, and PIDs, but only after you turn it on.

Command	What it does
	Enable completion (put in )
	Complete; a second Tab lists candidates
(with menu select)	Arrow-key menu over the candidates
	Turn on the arrow-key menu
	Case-insensitive completion
	Rebuild the cache when completions go stale
	Fix the "compinit: insecure directories" warning

Keybindings and Vi Mode

Command	What it does
	Emacs mode (the default)
	Vi mode: Esc for normal mode, back to insert
	List current bindings
	Restore Ctrl+R in vi mode (not bound there by default)
	Make Esc register instantly in vi mode (in )
	See what a specific key runs

In vi normal mode: / step through history, searches it, opens the line in your editor.

Globbing

zsh globbing does what you would otherwise need for. Recursive works out of the box.

Pattern	What it matches
	All .js files, recursively
	Regular files only
	Directories only
	Symlinks only
	The most recently modified file
	The five most recently modified
	Files larger than 10 MB
	All .txt except notes.txt (needs extendedglob)
	Everything except .md files (needs extendedglob)
	Files, and no error when nothing matches

setopt extendedglob   # enables ^negation and the ~exclusion operator

For heavier searches (by mtime, with -exec), see the find cheat sheet.

Startup Files

Read in this order. macOS Terminal and iTerm open login shells, so and both run; most Linux terminals open non-login shells, so only runs.

File	When it runs	Put here
	Every zsh, even scripts	Almost nothing; keep it minimal
	Login shells, once	PATH exports,
	Every interactive shell	Aliases, functions, prompt, keybindings, completion
	Login shells, after zshrc	Rarely used
	When a login shell exits	Cleanup, rarely used

After editing any of them: (or open a new tab).

Prompt

Command	What it does
	user@host, current directory, then % (# as root)
	Just the last path component
	Colour a segment ( on, off)
	Right-side prompt showing the time
	Enable the built-in theme system
	List built-in themes ( tries one)

Common escapes: user, host, directory with , % or #, time, last exit code. Most people skip hand-rolling and install powerlevel10k or starship, which come with git status, exit codes, and language versions built in.

Oh My Zsh

A config framework: themes, completion tweaks, and plugins in one install. Everything lives in after it is set up.

Command	What it does
	Enable plugins (edit the line in )
	Pick a theme
	Update Oh My Zsh
	List available plugins
	Apply config changes to the current session

The git plugin is why most people install it. The aliases you will actually use:

Alias	Expands to

/	/




	current branch




/	/

Run to see the full list (150+).

Command Not Found Fixes

means the binary is not on your PATH or is not a binary at all. The pattern is the same for brew, pip, npm, nvm, docker, and code.

Symptom	Fix
(Apple Silicon)	Add to , open a new tab
Any tool you know is installed	, then add its directory: in
Installed seconds ago, still not found	so zsh refreshes its command cache
	nvm is a function; its init lines belong in , run the installer again or copy them over
Worked in bash, gone in zsh	Move PATH exports from / into
	In VS Code: Cmd+Shift+P, "Shell Command: Install 'code' command in PATH"

One-Liners and Substitution

Command	What it does
	Run the second only if the first succeeds
	Run both regardless
	Run the second only if the first fails
	Capture a command's output in a variable
	Substitute output inline
	Arithmetic
	Loop over files on one line

zsh vs bash

Difference	zsh	bash
Unquoted with spaces	Stays one word	Splits into words
Array indexing	Starts at 1 ()	Starts at 0 ()
Recursive glob	Built in	Needs
Unmatched glob	Error:	Pattern passed through as-is
Config file
Prompt variable	with escapes	with escapes
Spelling correction, suffix aliases, glob qualifiers	Yes	No

Scripts are unaffected: a shebang runs the script in bash whatever your login shell is. Write new scripts for the shell you name in the shebang.

Gotchas

when a URL contains or : zsh globs the argument. Quote it () or .
comments do not work at the interactive prompt by default: (Oh My Zsh turns this on for you).
Pasted multi-line snippets run line by line as they land. Paste into (editor) if you want to review first.
A new PATH entry in only applies to new shells; fixes the current one.
zsh writes each terminal's history at exit by default; if you want tabs to see each other's commands live.
Long remote sessions die with the connection. Run zsh inside tmux on servers so your shell survives a dropped SSH connection.

zsh Cheat Sheet