A small script to find stale branches

find-old-branches.sh

#!/bin/bash

# This is a very naive script, it doesn't do grouping and returns all branches
# I only really care about branches that have not seen commits in two months
#
# I am hoping to find some time to write a tool that can output these reports for me
# In the meantime, I am using this

echo "Merged branches"
for branch in `git branch -r --merged | grep -v HEAD`;do echo -e `git log --no-merges -n 1 --format="%ci, %cr, %an, %ae, "  $branch | head -n 1` \\t$branch; done | sort -r

echo ""
echo "Not merged branches"
for branch in `git branch -r --no-merged | grep -v HEAD`;do echo -e `git log --no-merges -n 1 --format="%ci, %cr, %an, %ae, " $branch | head -n 1` \\t$branch; done | sort -r

Quickly hacked together a powershell version in case it helps anyone
`#! /usr/bin/pwsh

echo ""
echo "Not merged branches"
$branches = git branch -r --no-merged | grep -v HEAD
$output = @()
foreach( $branch in $branches ) {
$branch = $branch.Trim()
$output += git log -n 1 --format="%ci, %cr, %an, %ae, $branch" --no-merges --first-parent $branch | Sort-Object
}
echo $output`

Could you please suggest me how to list all the branches under enitirr gitlab

It's a good idea to change the column separators because the dates in the output contain ,, so another column separator like | is more appropriate to avoid confusion.
Just change --format="%ci, %cr, %an, %ae, " to --format="%ci | %cr | %an | %ae | ".