$ ./1.get_opt.pl --configfile C --outfile /home/bob/Documents/meditations/Algorithm-Markov-Multiorder-Learner-master/output/1.txt --infile /home/bob/Documents/meditations/Algorithm-Markov-Multiorder-Learner-master/data/2.short.shelley.txt
Use of uninitialized value $inFH in <HANDLE> at ./1.get_opt.pl line 34.
readline() on unopened filehandle at ./1.get_opt.pl line 34.
$ cat 1.get_opt.pl
#!/usr/bin/perl -w
use 5.011;
use Getopt::Long;
my $outfile    = undef;
my $configfile = undef;
my $infile     = undef;

if (
  !Getopt::Long::GetOptions(
    "outfile=s",
    \$outfile,
    "infile=s",
    \$infile,
    "configfile=s",
    \$configfile,
    "help",
    sub {
      print "Usage : $0 --configfile C [--outfile O] [--infile I] [--help]\n";
      exit 0;
    },
  )
  )
{
  die "error, commandline";
}
die "configfile is needed (via --configfile)" unless defined $configfile;
my $inFH;

if ( defined($infile) ) {

  open my $inFH, '<', $infile or die "opening input file $infile, $!";
}
my $instr;
{ local $/ = undef; $instr = <$inFH> }
if ( defined($instr) ) {

  say "input  is $instr";

}

$