git_prompt.rb

#!/usr/bin/ruby
host = `hostname`.chomp
user = ENV['USER'] || '???'
pwd = Dir.pwd
term = ENV['TERM'] || ''
x = ''

x << "\e]0;#{pwd}\a" if term =~ /xterm|rxvt/ # set window title
x << "\e[1;36;44m #{user}@#{host} \e[1;33;44m#{pwd} "

git_status = `git status 2>/dev/null`
if $?.exitstatus < 128
  git_branch = if git_status =~ /On branch (.*)/
                 $1
               else
                 '???'
               end

  x << "\e[1;36;44mgit: \e[1;35;44m#{git_branch} "

  changes = Hash.new {|h,k| h[k] = [] }
  curtype = nil
  
  git_status.lines.each do |line|
    case line
    when /Changes to be committed/
      curtype = :staged
    when /Changed but not updated/
      curtype = :unstaged
    when /(new file|modified|renamed|deleted):\s+(.*)/
      changes[curtype] << $2
    end
  end
  
  [[:staged,32],[:unstaged,31]].each do |t,c|
    unless changes[t].empty?
      s = changes[t].join ' '
      s = "(#{changes[t].size} files)" if s.size > 30
      x << "\e[1;#{c};44m#{s} "
    end
  end
end

x << "\e[00m"
puts x