Return file handle from subroutine and pass to other subroutine - perl

Question

I am trying to create a couple of functions that will work together. getFH should take in the mode to open the file (either > or < ), and then the file itself (from the command line). It should do some checking to see if the file is okay to open, then open it, and return the file handle. doSomething should take in the file handle, and loop over the data and do whatever. However when the program lines to the while loop, I get the error:
readline() on unopened filehandle 1
What am I doing wrong here?
#! /usr/bin/perl
use warnings;
use strict;
use feature qw(say);
use Getopt::Long;
use Pod::Usage;
# command line param(s)
my $infile = '';
my $usage = "\n\n$0 [options] \n
Options
-infile Infile
-help Show this help message
\n";
# check flags
GetOptions(
'infile=s' => \$infile,
help => sub { pod2usage($usage) },
) or pod2usage(2);
my $inFH = getFh('<', $infile);
doSomething($inFH);
## Subroutines ##
## getFH ##
## #params:
## How to open file: '<' or '>'
## File to open
sub getFh {
my ($read_or_write, $file) = #_;
my $fh;
if ( ! defined $read_or_write ) {
die "Read or Write symbol not provided", $!;
}
if ( ! defined $file ) {
die "File not provided", $!;
}
unless ( -e -f -r -w $file ) {
die "File $file not suitable to use", $!;
}
unless ( open( $fh, $read_or_write, $file ) ) {
die "Cannot open $file",$!;
}
return($fh);
}
#Take in filehandle and do something with data
sub doSomething{
my $fh = #_;
while ( <$fh> ) {
say $_;
}
}

Answer 1

my $fh = #_;
This line does not mean what you think it means. It sets $fh to the number of items in #_ rather than the filehandle that is passed in - if you print the value of $fh, it will be 1 instead of a filehandle.
Use my $fh = shift, my $fh = $_[0], or my ($fh) = #_ instead.

Answer 2

As has been pointed out, my $fh = #_ will set $fh to 1, which is not a file handle. Use
my ($fh) = #_
instead to use list assignment
In addition
-e -f -r -w $file will not do what you want. You need
-e $file and -f $file and -r $file and -w $file
And you can make this more concise and efficient by using underscore _ in place of the file name, which will re-use the information fetched for the previous file test
-e $file and -f _ and -r _ and -w _
However, note that you will be rejecting a request if a file isn't writeable, which makes no sense if the request is to open a file for reading. Also, -f will return false if the file doesn't exist, so -e is superfluous
It is good to include $! in your die strings as it contains the reason for the failure, but your first two tests don't set this value up, and so should be just die "Read or Write symbol not provided"; etc.
In addition, die "Cannot open $file", $! should probably be
die qq{Cannot open "$file": $!}
to make it clear if the file name is empty, and to add some space between the message and the value of $!
The lines read from the file will have a newline character at the end, so there is no need for say. Simply print while <$fh> is fine
Perl variable names are conventionally snake_case, so get_fh and do_something is more usual