For Rubyists who are using Mac, these are very handy in IRB:

    # stick in .irbrc
    def copy(str)
      IO.popen('pbcopy', 'w') { |f| f << str.to_s }
    end

    def paste
      `pbpaste`
    end

    def ep
      eval(paste)
    end

I knew of pbcopy/pbpaste, but never thought of that. Great idea,

Python version (adjust to pbcopy/pbpaste if on OS X): http://gist.github.com/488852

If you're running on Windows, Vista/W7 has `clip` as an equivalent to pbcopy. One project I was working on, the sysadmin didn't give us any access to the server, so we had to instruct him to use git each time an update went through (daily). `git rev-parse HEAD | clip` was the fastest way to get the "revision your tree should be at after pulling" then and send it to him.