I've had a look back at Split pattern doesn't match last line of file and I don't think your chomp; next unless $_; is going to cope if your data has lines containing just spaces (as implied in your OP), although it does cope with those that are just a newline. Given this data file

1st line
2nd line, next line is just a newline

4th line, next line spaces and newline
   
6th and last line
[download]

this script that uses your construct

use strict;
use warnings;

my $inFile = q{spw592594.dat};
open my $inFH, q{<}, $inFile
   or die qq{open: $inFile: $!\n};

while (<$inFH>)
{
    chomp;
    next unless $_;
    print qq{-->$_<--\n};
}

close $inFH
   or die qq{close: $inFile: $!\n};
[download]

produces

-->1st line<--
-->2nd line, next line is just a newline<--
-->4th line, next line spaces and newline<--
-->   <--
-->6th and last line<--
[download]

and, as you can see, the line with spaces does not get rejected and the empty line does. A string of spaces is boolean true. Changing the script to

...
while (<$inFH>)
{
    chomp;
    # reject if 0 or more spaces anchored to start and end
    next if m{^\s*$};
    print qq{-->$_<--\n};
}
...
[download]

does reject correctly and produces

-->1st line<--
-->2nd line, next line is just a newline<--
-->4th line, next line spaces and newline<--
-->6th and last line<--
[download]

I hope this is of use.

Cheers,

JohnGG

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