git-delete-merged-branches

#!/bin/bash
set -e

USAGE="usage: git delete-merged-branches
        [(-r|--remote) <remote-name>]
        [(-b|--branch) <merge-base>]
        [(-s|--older-than) <date>]
        [--local-only] [--yes] [-n|--dry-run]"

for (( i = 1; i < $(($#+1)); ++i )); do
  # echo "(option ${@:$i:1})"
  case "${@:$i:1}" in
    -r|--remote)
      REMOTE="${@:$((++i)):1}"
      ;;
    -b|--branch)
      BASE="${@:$((++i)):1}"
      ;;
    -s|--older-than)
      OLDER_THAN="${@:$((++i)):1}"
      ;;
    --local-only)
      LOCAL_ONLY=1
      ;;
    --yes)
      CONTINUE=yes
      ;;
    -n|--dry-run)
      DRY_RUN=-n
      ;;
    -h|--help)
      cat <<< $USAGE
      exit 0
      ;;
    *)
      echo "unknown option ${@:$i:1}">&2
      echo $USAGE>&2
      exit 1
      ;;
  esac
done

# REMOTE: remote name
if [ ! $LOCAL_ONLY ]; then
  if [ -z "$REMOTE" ]; then
    REMOTE=origin
    read -p "remote ($REMOTE): " REMOTE
  fi
  if [ -z "$REMOTE" ]; then
    REMOTE=origin
  else
    if [ ! $(git remote | grep -e "^$REMOTE\$") ]; then
      echo "not found: $REMOTE"
      exit 1
    fi
  fi
fi

# BASE: base branch/commit
if [ -z "$BASE" ]; then
  if [ -z "$REMOTE" ]; then
    BASE=master
  else
    BASE=$REMOTE/master
  fi
  read -p "base ($BASE): " BASE
fi
if [ -z "$BASE" ]; then
  if [ -z "$REMOTE" ]; then
    BASE=master
  else
    BASE=$REMOTE/master
  fi
elif [[ $BASE =~ ^HEAD ]]; then
  BASE=$(git rev-parse $BASE)
elif [ -z $(git branch --all --list $BASE) ]; then
  echo "branch not found: $BASE"
  exit 1
fi

# OLDER_THAN: to remove branch older than
if [ -z "$OLDER_THAN" ]; then
  OLDER_THAN="4 months ago"
  read -p "older than ($OLDER_THAN): " OLDER_THAN
fi
if [ -z "$OLDER_THAN" ]; then
  OLDER_THAN="4 months ago"
fi

if [ ! "$LOCAL_ONLY" -o -n "$REMOTE" ]; then
  REMOTE_REF=refs/remotes/$REMOTE/
fi

REFS=$(git for-each-ref \
  --format="%(refname:short)" \
  --sort=committerdate \
  --merged $BASE \
  $REMOTE_REF refs/heads/)

REFS=$(cat <<< $REFS | grep -v "$BASE" | grep -v "$REMOTE/master" | grep -v HEAD)

LOGFMT="%C(red)%h%Creset %C(cyan)%ci%Creset %C(green)(<branch>)%Creset %C(yellow)%cn%Creset %s"
TARGETS=

for BRANCH in $REFS; do
  P=$(sed "s|<branch>|$BRANCH|" <(echo "$LOGFMT"))
  if [ -n "$(git log -1 --oneline --since="$OLDER_THAN" $BRANCH)" ]; then
    git log -1 --pretty="remaining: $P" $BRANCH
  else
    git log -1 --pretty="deleting: $P" $BRANCH
    TARGETS="$TARGETS
    $BRANCH"
  fi
done

if [ -z "$TARGETS" ]; then
  echo no branch to delete
  exit 0
fi

if [ -z "$DRY_RUN" -a "$CONTINUE" != "yes" ]; then
  echo "delete branches..."
  read -p "continue? (yes/No): " CONTINUE
fi

CONTINUE=$(echo $CONTINUE | tr '[:upper:]' '[:lower:]')
if [ -z "$DRY_RUN" -a "$CONTINUE" == yes ]; then
  echo continue...
  for BRANCH in $TARGETS; do
    if [ -n "$REMOTE" ]; then
      if [[ "$BRANCH" =~ ^$REMOTE ]]; then
        git push $DRY_RUN $REMOTE :$(echo $BRANCH | sed "s/$REMOTE\///")
        continue
      fi
    fi
    if [ -n "$DRY_RUN" ]; then
      echo git branch -D $BRANCH 
    else
      git branch -D $BRANCH
    fi
  done
fi