Re: How do I Determine if my script is being piped to?

[kschwab]

You can tell if STDIN is a tty or not, which isn't quite the same thing, but it might suffice:

#!/usr/bin/perl
use POSIX qw(isatty);
if (isatty(STDIN)) {
   die("nope. not like that\n");
}
while (<>) {
   print "$_\n";
}

[netguy]

Thanks much for the reply. I didn't expect an answer so fast or that it would provide the solution.

Though the example you gave doesn't work, maybe because of 'use strict;' , I did find a couple things that do work. If I did have a better understanding of Linux, I may have found the answer on my own. Just something I'll have to work on.

Here are a couple examples of what did work for me:


use strict;

if ( -t STDIN ) {
    print "This is what you're supposed to do ...\n";
    exit;
}

# or 

use POSIX qw(isatty);
if ( isatty(\*STDIN) ) {
    print "This is what you're supposed to do ...\n";
    exit;
}

while (<STDIN>) {
    print STDOUT "Add something to STDOUT".$_;
}


Thanks for the help. It wasn't a show-stopping feature, just trying to mitigate confusion by some users when the command is run and the cursor just sits there doing nothing.

[boftx]

Well, kschwab has a much better memory that I do. You can pretty much ignore what I was posting at the same time he was giving you the answer I was looking for. :)