Delete merged local branches older than N days

git-delete-merged-local-branches.sh

#!/bin/bash

# delete merged local branches
days=90
found=0

# preview
# git branch --merged | grep -v -E "\\*|\bmaster\b|\bmain\b|\bdevelopment\b" | xargs -r -n 1

# list branches merged
# git branch --merged
# https://git-scm.com/docs/git-branch

# exclude master, main, development
# grep -v -E "\\*|\bmaster\b|\bmain\b|\bdevelopment\b"
# -v, --invert-match        select non-matching lines
# -E, --extended-regexp     \b word boundaries
# https://www.man7.org/linux/man-pages/man1/grep.1.html

# xargs -r -n 1
# -n max-args, --max-args=max-args; exit if greater
# -r, --no-run-if-empty; do not run if no results
# https://www.man7.org/linux/man-pages/man1/xargs.1.html

# git log -1 --since="$days days ago" -s $k
# gti log, one line, since $days days ago, for branch $k
# https://www.git-scm.com/docs/git-log

# delete branch
# git branch -d $k
# https://git-scm.com/docs/git-branch

echo "branches older than $days days:"
for k in $(git branch --merged | grep -v -E "\\*|\bmaster\b|\bmain\b|\bdevelopment\b" | xargs -r -n 1); do
  if [[ ! $(git log -1 --since="$days days ago" -s $k) ]]; then
    echo $k
    (( found++ ))
  fi
done

if [[ $found -eq 0 ]]; then
    echo "no branches found"
    exit 0
fi;

read -s -n 1 -p "press any key to delete $found branches older than $days days . . ."
echo ""

# run
for k in $(git branch --merged | grep -v -E "\\*|\bmaster\b|\bmain\b|\bdevelopment\b" | xargs -r -n 1); do
  if [[ ! $(git log -1 --since="$days days ago" -s $k) ]]; then
    git branch -d $k
  fi
done