A ruby shell script to switch git branches based on a regex

git-switch

#!/usr/bin/env ruby
search = Regexp.new(ARGV[0])
output = `git branch`
matching = output.lines.select{ |l| l.match(search) }
if matching.size == 0
  STDERR.puts "No branch matches #{ARGV[0]}"
elsif matching.size == 1
  `git checkout #{matching[0].strip}`
else
  puts "Multiple branches matched:"
  matching.each do |m|
    puts "  #{m.strip}"
  end
end