git-prune-local

#!/bin/bash

git branch --merged | while read line
do
    # If the line is in the format '* master' (indicating the current branch),
    # this will be effectively empty, so we don't somehow delete the current
    # branch
    BRANCH=`echo "$line" | awk -F '*' '{ print $1 }'`

    if [ -z "$BRANCH" ]
    then
        continue
    fi

    if [ "$BRANCH" == "master" ]
    then
        continue
    fi

    git branch -d "$BRANCH"
done