i dont think you can use -s to find the size of a line , you can use it to check the file size

# loop through my files 
foreach my $file ( @files ) {
my $size = -s "fullpathtofile/$file";
next if $size > $allowed_size;
# Do Some Proccessing for the file if it's not bigger than the allowed
+ size
}
[download]

HTH