Adding git branch on the Bash command prompt

by

git 1.9.3 or later: use __git_ps1

Git provides a shell script called git-prompt.sh, which includes a function __git_ps1 that

prints text to add to bash PS1 prompt (includes branch name)

Its most basic usage is:

$ __git_ps1
(master)

It also takes an optional format string:

$ __git_ps1 'git:[%s]'
git:[master]

How to Get It

First, copy the file to somewhere (e.g. ~/.git-prompt.sh).

Option 1: use an existing copy on your filesystem. Example (Mac OS X 10.15):

$ find / -name 'git-prompt.sh' -type f -print -quit 2>/dev/null
/Library/Developer/CommandLineTools/usr/share/git-core/git-prompt.sh

Option 2: Pull the script from GitHub.

Next, add the following line to your .bashrc/.zshrc:

source ~/.git-prompt.sh

Finally, change your PS1 to call __git_ps1 as command-substitution:

Bash:

PS1='[\u@\h \W$(__git_ps1 " (%s)")]\$ '

Zsh:

setopt PROMPT_SUBST ; PS1='[%n@%m %c$(__git_ps1 " (%s)")]\$ '

git < 1.9.3

But note that only git 1.9.3 (May 2014) or later allows you to safely display that branch name(!)

See commit 8976500 by Richard Hansen (richardhansen):

Both bash and zsh subject the value of PS1 to parameter expansion, command substitution, and arithmetic expansion.

Rather than include the raw, unescaped branch name in PS1 when running in two- or
three-argument mode, construct PS1 to reference a variable that holds the branch name.

Because the shells do not recursively expand, this avoids arbitrary code execution by specially-crafted branch names such as

'$(IFS=_;cmd=sudo_rm_-rf_/;$cmd)'.

What devious mind would name a branch like that? 😉 (Beside a Mom as in xkcd)

More Examples

still_dreaming_1 reports in the comments:

This seems to work great if you want a color prompt with xterm (in my .bashrc):

PS1='\[\e]0;\u@\h: \w\a\]\n${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\03‌​3[01;34m\]\w\[\033[00m\]$(__git_ps1)\$ '

Everything is a different color, including the branch.

In in Linux Mint 17.3 Cinnamon 64-bit:

PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[01;34m\] \w\[\033[00m\]$(__git_ps1) \$ '

As noted by J’e in the comments

Ubuntu

Modify PS1 assignments in your bashrc with,

PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\033[0;32m$(__git_ps1 " (%s)")\033[0m\$ '

# ---AND--- 

PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w$(__git_ps1 " (%s)")\$ '

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