use strict;
my $str = 'http://maven/artifactory/libs-snapshot/commons-lang/commons-lang/2.6/commons-lang-2.6.pom (18 KB at 221.9 KB/sec)';
my $regex = qr/\|(?=[^\(\)]*\))/p;
my $subst = '~';
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