A fish function which deletes all branches not called main or master

branchclean.fish

function branchclean
    # delete branches that are not called 'main' or 'master'
    # Invoke with -r to also delete the branches on the origin remote
    # WARNING — this doesn't check if the branches are merged.
    argparse 'r/remote' -- $argv

    for b in (git branch | grep -v "^\*\?\s\+\(master\|main\)\$" | string trim);
        git branch --delete $b;
        if test -n "$_flag_r"
            git push -d origin $b
        end
    end
end