#!/usr/bin/perl

use strict;

my ($arg_1, $arg_2) = @ARGV;
my $var;

$var = 'a';
$var =~ s@\x61@\x41@;       # works
print "$var\n";

$var = 'a';
$var =~ s@$arg_1@$arg_2@;   # no work
print "$var\n";

exit;


./arg.pl '\x61' '\x41'
A
\x41