• Copy this file to somewhere (e.g. ~/.git-prompt.sh).
• Add the following line to your .bashrc/.zshrc:

source ~/.git-prompt.sh

• 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)")]\$ '

但请注意，只有git 1.9.3(2014年5月)or later允许您安全地显示该分支名称(！)

见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)'.

什么愚蠢的心会命名这样的分支？ ;)(Beside a Mom as in xkcd)

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.

在Linux Mint 17.3肉桂64位：

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