Bash vs zsh Differences

Feature	Bash	zsh
Array starting index	0-based	1-based
Word splitting on variables	$var is split on spaces automatically	$var is not split (safer)
Glob (**)	Requires shopt -s globstar	Available by default
No-match glob	Pattern string is passed as-is	Raises an error (nomatch)
Prompt variables	\u, \h, \w	%n, %m, %~
Option settings	shopt -s option-name	setopt option-name
Config file	~/.bashrc	~/.zshrc
Completion system	bash-completion (external)	compinit / compsys (built-in)
Right prompt	Not available	Configurable via RPROMPT
Spell correction	Not available	Enabled with setopt correct

Array starting indices differ. bash uses 0-based indexing; zsh uses 1-based indexing.

bash

fruits=("apple" "banana" "cherry")
echo ${fruits[0]}
apple
echo ${fruits[1]}
banana

zsh

fruits=("apple" "banana" "cherry")
echo ${fruits[1]}
apple
echo ${fruits[2]}
banana

In bash, an unquoted variable is automatically split on spaces. In zsh, it is not split.

bash

msg="hello world"
for word in $msg; do echo "[$word]"; done
[hello]
[world]

zsh

msg="hello world"
for word in $msg; do echo "[$word]"; done
[hello world]

Use the recursive glob (**) to search files in subdirectories. In bash, you must first run shopt -s globstar.

bash

shopt -s globstar
ls **/*.txt

zsh

ls **/*.txt

The behavior when a glob matches no files differs. bash passes the pattern string as-is, while zsh raises an error.

bash

ls *.xyz
ls: *.xyz: No such file or directory

zsh

ls *.xyz
zsh: no matches found: *.xyz

Prompt configuration syntax differs.

bash (~/.bashrc)

PS1='\u@\h:\w\$ '

zsh (~/.zshrc)

PS1='%n@%m:%~%# '

Meaning	Bash	zsh
Username	\u	%n
Hostname	\h	%m
Current directory	\w	%~
Prompt symbol (# for root)	\$	%#

Shell option syntax differs.

bash

shopt -s nocaseglob
shopt -s globstar
shopt -u nocaseglob

zsh

setopt no_case_glob
setopt glob_star_short
unsetopt no_case_glob

A shell script written with #!/bin/bash always runs under bash syntax, so using zsh as your daily shell does not affect script behavior. The differences matter when you type commands directly in the terminal or when writing settings in ~/.bashrc vs ~/.zshrc.

The most important difference to watch for is the array starting index. bash is 0-based and zsh is 1-based, so the same code can produce different results. If portability matters, specify #!/bin/bash explicitly and run the script with bash.

For shebang usage, see shebang / chmod +x. For variable expansion, see ${Parameter Expansion}. For glob usage in for loops, see for.