Keeping old branches clean. Run this and it will delete fully merged branches.

branch_clean.scala

#!/bin/sh
exec scala -savecompiled "$0" "$@"
!#
// Get the shell scripting enrichments
import scala.sys.process._

val alwaysKeep = Set("develop", "master")

// Now delete any merged branches"
val branches: String = "git branch".!!

// Have to use augmentString explicitly because the process implicits conflict
augmentString(branches)
  .lines
  .map { line => if(line(0) == '*') line.drop(1).trim else line.trim }
  .filterNot(alwaysKeep)
  .foreach { branch =>
    ("git branch -d %s".format(branch)).!
  }