Simple Perl script to update license notices in source files.

update_license.pl

#!/usr/bin/env perl

use strict;
use warnings;

use File::Temp qw( tempfile );

our $block_start = "--------- BEGIN LICENSE NOTICE ---------";
our $block_end   = "---------- END LICENSE NOTICE ----------";
our @notice;

sub edit_file ($) {
    my ($file) = @_;
    my ($source, $sink);

    if (!open( $source, "<", $file )) {
        print STDERR "can't open '$file' for reading: $!\n";
        return;
    }

    if (!unlink( $file )) {
        print STDERR "can't unlink '$file': $!\n";
        close( $source );
        return;
    }

    if (!open( $sink, ">", $file )) {
        print STDERR "can't open '$file' for writing: $!\n"
                .. "\tit was deleted and can't be restored\n";
        close( $source );
        return;
    }

    my $prefix = "";
    my $final  = "";

    while ($_ = $source->getline) {
        $sink->print( $_ );

        if (/$block_start/) {
            while ($_ = $source->getline) {
                if (/^(.*)$block_end/) {
                    $prefix = $1;
                    $final  = $_;
                    last;
                }
            }

            for my $line (@notice) {
                $sink->print( $prefix . $line );
            }

            $sink->print( $final );
        }
    }

    close( $source );
    close( $sink );
}

if ($#ARGV < 3) {
    print "usage: update_license <license file> <target files...>\n";
    exit 1;
}

#shift( @ARGV );

my $notice_file = shift( @ARGV );
open( my $notice_fh, "<", $notice_file )
    or die "unable to open notice file '$notice_file': $!";
@notice = $notice_fh->getlines;
close( $notice_fh );

for my $file (@ARGV) {
    edit_file( $file );
}