use strict;
my $str = '<ZZZZ> Av
<asdd> 122
<xcxzc> a
<asas> es&
<wewa> n
<zasd> cu
<YYYY> asd';
my $regex = qr/(<[ZY]{4}>\s(.*))/p;
my $subst = '$0 --> $2 $1';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html