How to remove all branches from a git repository based on a divergence threshold from master?

Question

On my project I need to clean up a repository that has hundreds of old branches that are no longer relevant.

I would like to remove the branches that have more than 1000 revisions away from master.

I found the command to find out the number of divergence of a branch:

git rev-list --count master...release/2.49.0

output: 1299

I don't see how to use the git for-each-ref command.

Is it possible to have a command that parse branch, count divergence and if the threshold is reach, perform a delete?

Answer 1

Use git for-each-ref to get all branches, then iterate for each to get the number (add a leading 0 for error)

git for-each-ref refs/remotes --format="%(refname)"| sed 's!refs/remotes/!!g'| while read branch; do
 nb=$(git rev-list --count main...$branch)
 if [ $nb -ge 5000 ]; then
 echo "$branch to delete"
 fi
done

just replace echo "$branch to delete" by git branch -D $branch

Answer 2

Thanks for all Ôrel.

Finally here is the code I used on the repo:

    git branch -r --format='%(refname:short)' | while read branch; do
    fromBranch=develop
    nb=$(git rev-list --count $fromBranch...$branch)
    subject="$branch"
    prefix="origin/"
    branchName=${subject#"$prefix"}
    if [ $nb -ge 1000 ]; then
        echo "$branchName diverged from $fromBranch by $nb revisions"
        # Uncomment to delete branch on remote
        # git push origin --delete $branchName      
    fi
done