use File::Slurp;
use warnings;
use strict;

my %PATTERNS =(
	'http://www.abc.com/test\b' => 'http://www.test.com/twist',
	'http://www.abc.com/(?:test[\d])\b' => 'http://www.test.com/',
);

# patterns to regexps
my @REGEXPS = map { qr/$_/ } keys %PATTERNS;


# read from commandline
die "usage: $0 <filenames> ...\n" unless @ARGV;

for my $filename (@ARGV){

	die "NOT A FILE! '$filename' " unless -f $filename;
	die "NOT READABLE! '$filename' " unless -r $filename;

	# read in a whole file into an array of lines 
	my $lines = read_file( $filename );

	my $changes = 0;

	for my $r (@REGEXPS){
		if($lines =~ $r){
			$changes++;
			last;
		}
	}

	if($changes == 0){
		print "no changes for $filename\n";
		exit 0;
	}

	rename $filename, $filename . ".bak";

	my ($r,$s);
	for $r (keys %PATTERNS){
		$s = $PATTERNS{$r};
		$lines =~s/$r/$s/gei;
	}

	# write out a whole file 
	write_file( $filename, $lines );

	print "Modified $filename\n";

}