git-ps1

.git-ps1.bash

function git-ps1 {
  case $1 in
    y|yes|on)
      export GIT_PS1_SHOWDIRTYSTATE=yes
      export GIT_PS1_SHOWUNTRACKEDFILES=yes
      if [ -n "$SSH_CLIENT" ] || [ -n "$SSH_TTY" ]; then
        export PS1='\[\e[0m\e[36m\]\u@\h \[\e[1;39m\]\w\[\e[0;32m\]$(__git_ps1 " (%s)")\[\e[0m\] \\$ ';
      else
        export PS1='\[\e[0m\e[31m\]\u \[\e[1;39m\]\w\[\e[0;32m\]$(__git_ps1 " (%s)")\[\e[0m\] \\$ ';
      fi
      echo
      ;;
    n|no|off)
      export GIT_PS1_SHOWDIRTYSTATE=no
      export GIT_PS1_SHOWUNTRACKEDFILES=no
      if [ -n "$SSH_CLIENT" ] || [ -n "$SSH_TTY" ]; then
        export PS1='\[\e[0m\e[36m\]\u@\h \[\e[1;39m\]\w\[\e[0m\] \\$ ';
      else
        export PS1='\[\e[0m\e[31m\]\u \[\e[1;39m\]\w\[\e[0m\] \\$ ';
      fi
      echo
      ;;
    *) echo 'usage: git-ps1 (y|yes|on|n|no|off)' ;;
  esac
}

.profile

source ~/.git-ps1.bash
git-ps1 on

Put .git-ps1.bash to your home directory ~ and add the lines from .profile to your .profile (or .bashrc or whatever). Your new Bash prompt will show in green your current Git branch and whether there are staged (+) or unstaged (*) changes or untracked files (%).

If you're working with a huge repository and updating the prompt is taking a lot of time, you can temporarily turn off the green part by calling git-ps1 off (or git-ps1 no or git-ps1 n).