use strict;
use warnings;

my $line  = "System has tool zigzag version 3.6";

my $match = 'System\s+has\s+tool\s+([0-9a-zA-Z_-]+)\s+version\s+(.*)';
my $replace = '"System has tool $1 version ABC"';

$line =~ s/$match/$replace/eeg;
print "Line after replacement: $line \n";