#!/usr/bin/perl -i

use strict;
use warnings;

my $z = 0;

# read stdin and any/all files passed as parameters one line at a time
while (<>) {
    # if we find a Z word, save it
    $z = $1 if /Z(\d+(\.\d+)?)/;

    # if we don't have Z, but we do have X and Y
    if (!/Z/ && /X/ && /Y/ && $z > 0) {
        # chop off the end of the line (incl. comments), saving chopped section in $1
        s/\s*([\r\n\;\(].*)//s;
        # print start of line, insert our Z value then re-add the chopped end of line
        print "$_ Z$z $1";
    }
    else {
        # nothing interesting, print line as-is
        #print;
    }
}