Clean up local branches that are already on master (credit to original gist)

gistfile1.sh

function git-branch-current() {                                         
  printf "%s\n" $(git branch 2> /dev/null | grep -e ^* | tr -d "\* ")   
}                                                                       
                                                                        
function git-branch-cleanup() {                                         
  local currentBranch=$(git-branch-current)                             
  local otherBranch=                                                    
  for otherBranch in $(git branch | grep -v $currentBranch) ; do        
    printf "Branch %s:\n" "$otherBranch"                                
    printf "  HEAD commit is: %s\n" "$(git log --oneline -n 1 $otherBranch)"
    local gerritChangeId=$(git log --format=full -n 1 $otherBranch | tail -1 | cut -d ':' -f 2)
    if ! [ "$gerritChangeId" ] ; then                                   
      printf "  HEAD of %s does not have a Gerrit Change-Id\n" "$otherBranch"
      continue                                                          
    fi                                                                  
    local mergedCommit=$(git log --oneline -n 1 --grep="$gerritChangeId" $currentBranch)
    if [ "$mergedCommit" ] ; then                                       
      printf "  Commit merged to %s: %s\n" "$currentBranch" "$mergedCommit"
      local reply                                                       
      read -p "  Delete branch $otherBranch  [y/N]? " reply             
      reply=${reply:-n}                                                 
      if [ $reply = "y" ] ; then                                        
        git branch -D $otherBranch                                      
      fi                                                                
    else                                                                
      echo "  Branch unmerged, moving on"                               
    fi                                                                  
  done                                                                  
}                                                                       
                                                                        
git-branch-cleanup