Question

I’ve got this little nifty thing in my .bashrc:

has_gitbranch() {
  if [ -e .git ]; then
    GIT_BRANCH='$(__git_ps1 "%s")'
    [ "$GIT_BRANCH" != 'master' ] && export PS1="$GIT_BRANCH$PS1"
  fi
}

venv_cd () {
   cd "$@" && has_gitbranch
}
alias cd="venv_cd"

(I didn’t write it myself and can’t remember where I got it from)

The problem is that if I enter a directory that is a git repo this happens:

reponamepeterbe@computername:~/directory $

That’s fine but what happens if I enter that directory again (e.g cd .) then this happens:

reponamereponamepeterbe@computername:~/directory $

And again:

reponamereponamereponamepeterbe@computername:~/directory $

How can I change the bash if statement so that it doesn’t prepend the git branch name if it’s already in $PS1?

If it was Python I would just do this:

GIT_BRANCH = get_current_git_repo_name()
if GIT_BRANCH not in PS1: # or PS1.find(GIT_BRANCH) == -1
      PS1 = GIT_BRANCH + PS1

Answer 1

case "$PS1" in
"$GIT_BRANCH"*)
    ;;
*)
    PS1="$GIT_BRANCH$PS1"
    ;;
esac

That said, you’re solving the wrong problem; I would store the basic PS1 value somewhere else and always build PS1 from that and the current repo name. Consider what will happen if you cd /some/other/repo.