Question

I have a program where I need to pass a filename (and location) to the program. How can I do this? I have read the GetOpt doc so please don’t point me there. My command line is as follows:

perl myprogram.pl -input C:\inputfilelocation -output C:\outputfilelocation

My GetOptions look like this:

GetOptions(‘input=s’ => \$input,’output=s’ => \$output);

Basically I need to figure out how to access that file in a while loop that I have which iterates over the lines in the file and puts each into $_

while ($input) {

…doesn’t work. Note that before my file worked fine with:

open my $error_fh, '<', 'error_log';
while (<$error_fh>) { 

Answer 1

This works for me. Your GetOptions seems correct. Open file and read from the filehandle, and don’t forget to check for errors:

use warnings;
use strict;
use Getopt::Long;

my ($input, $output);
GetOptions('input=s' => \$input,'output=s' => \$output) or die;

open my $fh, '<', $input or die;

while ( <$fh> ) { 
    ## Process file.
}