#!usr/bin/perl -Tw

use warnings;
use strict;

opendir my $dh, './testdir/'; #assume all files, no sub dirs 

my @filelist = readdir($dh);

close($dh);

my $rep = qr'<>';

while (@filelist){

my $basefile = shift @filelist;

 next unless $basefile =~ m/^((\w+\s*)+\.(pl|txt))$/;
 $basefile = $1;
 my $pathfile = './testdir/'.$basefile;

 open (my $rfh, '<', $pathfile);

 my @filelines;

 while (<$rfh>){
 
 $_ =~ s/$rep/\`<>\`/g;

 push @filelines, $_;

 }

 close($rfh);

 open (my $wfh, '>', $pathfile);

 while (@filelines){

 my $line = shift @filelines;

 print $wfh $line;

 }

 close($wfh);

}

exit 0;