Script to delete branches older than a certain date

delete_branches_older_than.sh

#!/bin/sh

date=$1

for branch in $(git branch -a | sed 's/^\s*//' | sed 's/^remotes\///' | grep -v 'master$'); do
  if [[ "$(git log $branch --since $date | wc -l)" -eq 0 ]]; then
    if [[ "$branch" =~ "origin/" ]]; then
      local_branch_name=$(echo "$branch" | sed 's/^origin\///')
      if [[ "$DRY_RUN" -eq 1 ]]; then
        echo "git push origin :$local_branch_name"
      else
        git push origin :$local_branch_name
      fi
    else
      if [[ "$DRY_RUN" -eq 1 ]]; then
        echo "git branch -D $branch"
      else
        git branch -D $branch
      fi
    fi
  fi
done

how is the date format?

It uses the git since syntax. Here is what I found in the examples section of the man log

git log --since="2 weeks ago" -- gitk
   Show the changes during the last two weeks to the file gitk. The "--" is necessary to avoid confusion with the branch named gitk

I've created an alternative that will make (I think) one git request to the remote instead of one for each branch:

https://gist.github.com/redthor/3776c1f726cafff41c9eda6f271466c3

Also the date format that works is like "2018-01-01" (using "2 weeks ago" with spaces will fail)