Bash script for cleaning up old git branches from local and remote repositories

git-branch-cleaner

#!/bin/bash

ME=$(basename $0)

function showHelp {
cat << EOF
Clean-up old git branches

Usage: $ME local show-last [AGE_IN_WEEKS]
       $ME remote show-last REMOTE [AGE_IN_WEEKS]
       $ME [-d] local remove-old AGE_IN_WEEKS 
       $ME [-d] remote remove-old REMOTE AGE_IN_WEEKS 
       $ME -h

Options:

  AGE_IN_WEEKS  Only include branches this many weeks old, or older
  REMOTE        Local alias for the remote repository
  -h            Show this help message and exit
  -d            Dry-run. Show what will be done if this flag is omitted

Examples:

  Show who the last committer of each branch was. Here 'origin' is the
  local alias for the remote repository. For a list of remote repositories
  aliased to your local repository, run `git remote -v`:

    $ME remote origin show-last

  Note that this shows the committer, not the author. These can differ if
  someone cherry-picked or merged a commit.

  Remove local branch references for braches older than a year:

    $ME local remove-old 52

  Show the remote branches that will be removed with the dry-run flag:

    $ME remote -d remove-old origin 80

  Actually remove remote branches older than 80 weeks:

    $ME remote remove-old origin 80
EOF
}

function showTooFewArguments {
cat << EOF
ERROR:
  Arguments missing. Which operation do you want to perform?

EOF
showHelp
}

function ageInWeeks {
    local NOW=$(date +%s)
    local SECONDS=$(( $NOW - $1 ))
    local DAYS=$(( $SECONDS / 604800 ))
    eval "$2"="$DAYS"
}

DRY_RUN=false
# Parse the short flags.
while getopts "h?d" opt; do
    case $opt in
        "h")
            showHelp
            exit
            ;;
        "?")
            showHelp
            exit
            ;;
        "d")
            DRY_RUN=true
            ;;
    esac
done

# Done with the short flags, shift over to the remaining arguments.
shift $(($OPTIND - 1))

# Parse the command line arguments.

if [ $# -eq 0 ]; then
    # Called without arguments, show help and exit.
    showHelp
    exit
fi


# Is the current dir a git repo?
git status > /dev/null || exit

TARGET=$1
ACTION=$2
MIN_AGE=
REMOTE=

if [ "$TARGET" == "local" ]; then
    MIN_AGE=$3
    if [ $# -lt 2 ]; then
        showTooFewArguments
        exit 1;
    fi
    echo "Working on local branches only."
elif [ "$TARGET" == "remote" ]; then
    REMOTE=$3
    MIN_AGE=$4
    if [ $# -lt 3 ]; then
        showTooFewArguments
        exit 1;
    fi
    echo "Working on remote branches only."
else
    showHelp
    exit 1
fi
echo


echo "Last committer of each branch:"    
echo

if [ -z "$MIN_AGE" ]; then
    MIN_AGE=0
fi

# The following lists the branches. This is the same for show-last and remove-old.
BRANCHES=
if [ "$TARGET" == "local" ]; then
    BRANCHES=$(git branch --no-color --no-abbrev -v)
else
    BRANCHES=$(git ls-remote -h $REMOTE)
fi
BRANCH_LIST=''
BRANCH_NAMES=();
while read -r BRANCH
do
    NAME=
    SHA=
    if [ "$TARGET" == "local" ]; then
        NAME=$(echo "$BRANCH" | sed -e 's/* /  /' | awk '{ print $1 }')
    else
        NAME=$(echo "$BRANCH" | sed -e 's^refs/heads/^^' | awk '{ print $2 }')
    fi

    if [[ $NAME =~ .*/HEAD ]]; then
        continue
    fi

    SHA=
    if [ "$TARGET" == "local" ]; then
        SHA=$(echo "$BRANCH" | sed -e 's/* /  /' | awk '{ print $2 }')
    else
        SHA=$(echo "$BRANCH" | awk '{ print $1 }')
    fi

    AGE=""
    ageInWeeks $(git log -n 1 --format=format:"%ct" $SHA) AGE
    if [ $AGE -lt $MIN_AGE ]; then
        continue
    fi

    BRANCH_NAMES+=("$NAME")
    BRANCH_LINE="$(printf '%-60s %4s %-12s' "${NAME}:" $AGE 'weeks') $(git log -n 1 --format=format:"%cN <%cE>" $SHA)"
    BRANCH_LIST+="${BRANCH_LINE}\n"
done <<< "$BRANCHES"

if [ ${#BRANCH_NAMES[@]} -eq 0 ]; then
    echo "No branches matching these criterea found."
    exit
fi

# Sort by age.
printf "$BRANCH_LIST" | sort -k2 -n

if [ "$ACTION" == "remove-old" ]; then 
    echo

    if [ $DRY_RUN == true ]; then
        if [ "$TARGET" == "local" ]; then
            echo "These local branches will be removed if you leave out the -d flag."
        elif [ "$TARGET" == "remote" ]; then
            echo "These remote branches will be removed from the remote repo if you leave out the -d flag."
        fi
    else
        # Read one character from console.
        read -p "Remove these branches older than $MIN_AGE weeks. Are you sure? [y/N] " -n 1 -r
        echo
        if [[ $REPLY =~ ^[Yy]$ ]]
        then
            echo "Removing branches..."
            for BNAME in "${BRANCH_NAMES[@]}"; do
                echo "${BNAME}..."
                if [ "$TARGET" == "local" ]; then
                    git branch -D $BNAME
                elif [ "$TARGET" == "remote" ]; then
                    git push $REMOTE :$BNAME
                fi
            done
        else
            echo "Aborting."
        fi
    fi

    echo
fi