I'd write it like this:

use strict;

open my $in, '<', "G203.xml" || die "Cannot open file: $!\n";
open my $out,'>' "_G203.xml" || die "Cannot open file: $!\n";

while (my $string1 = <$in>) {
  $string1 =~ s/XXXGASPOINTIDXXX/656563/gi;
  $string1 =~ s/XXXMMREFXXX/62394732472856563/gi;
  print $out $string1;
}

close $in;
close $out;
[download]

Notes:

• I use the 3 argument form of 'open'.
• I read from the file one line at a time, using 'while', process each line, then write it out. No need to hold all the lines in memory (in an array).
• There's no need to sleep.
• There's no need to loop over the entire file twice: you can do both regex's inside a single loop. Two passes might be necessary if the patterns somehow overlapped, but these don't seem to do so).

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.