branch-rot.sh

#!/bin/env bash
# git branch freshness test.
# branch-rot.sh [expiration-date-epoc-seconds]
# default expiration date is about one month ago

# seconds*minutes*hours*days*weeks*months ~ one month ago
expiration_date=$(( $(date +%s) - 60*60*24*7*4 ))
if [[ $# -eq 1 ]]; then
    expiration_date=$1
fi

for branch in $(git branch -r --merged master | grep -v HEAD); do
    # last commit on a branch git log with reflog date in seconds rendering only reflog date extracting unix seconds time
    reflog_date=$(git log -g -n 1 --date=raw --pretty=%gd $branch -- | sed 's/.*{\(.*\) .*/\1/')
    if [[ -n "$reflog_date" && "$reflog_date" -lt "$expiration_date" ]]; then
        echo "stale $branch ($(date -d @$reflog_date))"
    else
        echo "fresh $branch ($(date -d @$reflog_date))"
    fi
done