Save jira-co.rb to a folder on your $PATH (for example ~/bin). Add git alias to your ~/.gitconfig

jira-co.rb

#!/usr/bin/env ruby

pattern = ARGV[0]
if pattern.to_s == ""
  puts "Must supply a pattern for the branch. i.e. RUBY-2379"
  exit 1
end

branches = `git branch -a | grep "remotes" | grep -i #{pattern}`.split("\n").map(&:strip)

if branches.size == 0 
  puts "No branch matched #{pattern.inspect}"
  exit 1
end

def shorten_branch_name branch_name
  branch_name.split("/").last
end

if branches.size == 1
  branch_name = shorten_branch_name branches[0]
  puts "checking out branch: #{branch_name.inspect}"
  `git checkout #{branch_name}`
else
  puts "Too many branches returned! Improve your pattern to match specific branch"
  branches.each_with_index do |branch, index|
    puts "#{index}: #{branch.inspect}"
  end
end