Hi burszuras,

You may also be interested in the -t file test (on line 23):

    -t  Filehandle is opened to a tty.
[download]

which is a nice way to discover whether you're at the tail end of a pipe or not.

For example:

#!/usr/bin/perl

use strict;
use warnings;
use feature qw( say );
use File::Basename;

my $iam = basename($0);

if (-t *STDIN) {
    my $nargs = @ARGV;
    say "Script '$iam' called from a terminal with $nargs arg(s):";
    for (my $idx = 0; $idx < $nargs; $idx++) {
        printf "  %2d.  %s\n", $idx+1, $ARGV[$idx];
    }
} else {
    say "Script '$iam' is receiving input from a pipe";
}
[download]

Call the above script like this: ./script arg1 arg2 arg3 and you get:

Script 'script' called from a terminal with 3 arg(s):
   1.  arg1
   2.  arg2
   3.  arg3
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If you call it like this, instead: echo Pipe to script | ./script then you'll get this:

Script 'script' is receiving input from a pipe
[download]

In the latter case, you could then do:

    while (<STDIN>) {
        say "Got input:  $_";
    }
[download]

or similar, to handle the piped data as you desire.