#!/usr/bin/perl -i

use strict;
use warnings;

# read identity from git config
my $name = `git config user.name`; chomp $name;
my $email = `git config user.email`; chomp $email;
my $identity = "$name <$email>";

my $last_signed = '';

while (<>) {
    if (/^Signed-off-by: \Q$identity\E\n/) {
	$last_signed = $ARGV;
    } elsif (/^---\n/ && $last_signed ne $ARGV) {
	# insert signature here
	print "Signed-off-by: $identity\n";
	$last_signed = $ARGV;
    }
    print;
}