Which branches "change" this file, compared to the current branch?

git-changefile

#!/usr/bin/perl
use strict;
use warnings;
use File::Basename qw<basename>;

my $file = shift
    or die basename($0), ": need a file\n";

my @branches = map {
    chomp;substr($_,2)
} qx!/usr/bin/git branch!;
for my $b (@branches) {
    my @diff = qx!/usr/bin/git diff $b -- $file!;
    next if !@diff;
    print "***** DIFF FOR BRANCH $b *****\n";
    print "@diff";
}