@files = grep { /\.log$/ } readdir ($DIR);
foreach my $x (@files){
open READFILE, "......";
open WRITEFILE, ">......";
while(<READFILE>){
chomp;
my @parts = split(/\s/, $_);
print WRITEFILE $parts[1], " ", $parts[0], "\n";
}
close WRITEFILE;
close READFILE;
[download]

That's my point. -z is looking for a zero byte file, but 'no content' could be a bunch of tabs and spaces.

[forda@hqnagtl1 ~]$ touch emptytest1
[forda@hqnagtl1 ~]$ touch emptytest2
[forda@hqnagtl1 ~]$ ls -l emptytest*
-rw-rw-r--  1 forda forda 0 Oct 22 17:19 emptytest1
-rw-rw-r--  1 forda forda 0 Oct 22 17:19 emptytest2
[forda@hqnagtl1 ~]$ echo '              ' >> emptytest2
[forda@hqnagtl1 ~]$ ls -l emptytest*
-rw-rw-r--  1 forda forda  0 Oct 22 17:19 emptytest1
-rw-rw-r--  1 forda forda 15 Oct 22 17:20 emptytest2
[download]

I put some spaces into a formerly empty file and now it has a size of 15.

non-Perl: Andy Ford

wht command did you select for getting such an output???