linux 命令行终端显示git 当前所在分支

#show the current git branch
find_git_branch () {
local dir=. head
until [ "$dir" -ef / ]; do
if [ -f "$dir/.git/HEAD" ]; then
head=$(< "$dir/.git/HEAD")
if [[ $head = ref:\ refs/heads/* ]]; then
git_branch="(*${head#*/*/})"
elif [[ $head != '' ]]; then
git_branch="(*(detached))"
else
git_branch="(*(unknow))"
fi
return
fi
dir="../$dir"
done
git_branch=''
}

PROMPT_COMMAND="find_git_branch; $PROMPT_COMMAND"
PS1="\u@\h:\w\[\033[0;32m\]\$git_branch\[\033[0m\] \$ "