#! /usr/bin/env perl
use strict;
use warnings;
use File::Slurp qw/slurp/;
# I am a unix filter!
die "usage: <pattern> <file>\n" unless @ARGV == 2;
my $p = $ARGV[0];
my $fc = slurp $ARGV[1];
while (defined($_ = <STDIN>)) {
  s/\Q$p/$fc/;
  print
}