#!/usr/bin/perl
# Created:
# 	10-02-04 	Sapan Bhatia

use strict;

my $rmask;
my $fmask;
my $smask;

if ($#ARGV<1 || $#ARGV>2) {
    die "Usage: s.pl <file regex> <search regex> <replace regex>\n";
}

if ($#ARGV==1) {
    $rmask="";
}
else {
    $rmask=$ARGV[2];
}
    
$fmask=$ARGV[0];
$smask=$ARGV[1];

recurse_dir($ENV{PWD});
exit(0);

sub recurse_dir {
    my @list;
    my $dir=shift;
    my $count;
    opendir CWD,$dir;
    @list=readdir(CWD);
    closedir CWD;
    shift @list;
    shift @list; 
    for (@list) {
	if (-d $dir."/$_") {
		recurse_dir($dir."/$_");
	}
	else {
	    if (-f "$dir/$_" && "$_"=~/$fmask/) {
		my @lines;
		open FIL,"+<$dir/$_";
		@lines=<FIL>;
		$count=0;
		map $count+=s/$smask/$rmask/g,@lines; 
		print "Processing $dir/$_... $count substitutions made\n";
		seek FIL,0,0;
		for (@lines) {
		    print FIL $_;
		}
		close FIL;
	    }
	}
    }
}