File to take @ARGS or "<" Redirect

awohld has asked for the wisdom of the Perl Monks concerning the following question:

I have a script that needs to take @ARGS or the "<" redirect.

%perl script.pl 7 12 5

or

%perl script.pl < text.txt #where the contents of the text file are 7 
+12 5
[download]

If there aren't @ARGS or a "< text.txt" I need it to print a message saying "use args or <".

I think I'm on the right track but I can't really get it to work.

Here's my code:

if(@ARGV)
{ my @node_numbers= @ARGV}
else
{ my @node_numbers = do { local $/; split ' ', <> };}

if (!@node_numbers) 
{
print <<"EOF";
#####################################
#
#  use args or < a text file
# 
#####################################
EOF
die;
}

# Do rest of code after here using @node_numbers
[download]

This is an addon to an older semi-related node

Comment on File to take @ARGS or "<" Redirect Select or Download Code

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Re: File to take @ARGS or "<" Redirect by ikegami (Patriarch) on Apr 20, 2005 at 19:41 UTC
If you're really asking how to detect if STDIN is a terminal (when @ARGV is empty), I think the following works: `my @node_numbers; if (@ARGV) { @node_numbers = @ARGV; } else { die(<<"EOF") if -t STDIN; ##################################### # # use args or < a text file # ##################################### EOF { local $/; @node_numbers = split(' ', <STDIN>); } } # Do rest of code after here using @node_numbers` [download]	[reply] [d/l]
Re^2: File to take @ARGS or "<" Redirect by awohld (Hermit) on Apr 20, 2005 at 19:48 UTC
Perfect! That's exactly what I needed!!!!!! Awesome you guys are always a great help!!!	[reply]
Re^3: File to take @ARGS or "<" Redirect by tcf03 (Deacon) on Apr 20, 2005 at 19:50 UTC
~~which one did the trick? Don't keep us in suspense.~~ Sorry, didnt realize how that sounded when I wrote it. Ted	[reply]
Re: File to take @ARGS or "<" Redirect by Roy Johnson (Monsignor) on Apr 20, 2005 at 19:35 UTC
You've scoped @node_numbers local to the blocks of the if. The @node_numbers you're using outside those blocks is not the same variable (it's a global -- you should `use strict;`). Once you fix that, if you run it from the command line, it's going to try to get data from STDIN, which will generally be the keyboard. You'll get the error-out if you redirect from /dev/null. Caution: Contents may have been coded under pressure.	[reply] [d/l]
Re^2: File to take @ARGS or "<" Redirect by awohld (Hermit) on Apr 20, 2005 at 19:39 UTC
@node_numbers should be global. So I'll do `use strict`	[reply] [d/l]
Re: File to take @ARGS or "<" Redirect by tcf03 (Deacon) on Apr 20, 2005 at 19:38 UTC
is this what you mean? `#!/usr/bin/perl die("no arg!") unless $ARGV[0]; print "\$ARGV[0] = $ARGV[0]\n";` [download] Ted	[reply] [d/l]