Re: Testing <>

You can detect the presence of waiting input using select, like:

use strict;
use warnings;

my $vector = '';
vec($vector,fileno(STDIN),1) = 1;
if (select($vector,undef,undef,0.01)) {
    while (<>) {
        print;
    }
}
[download]

where I have set a 10 millisecond timeout. Might be easier and more portable though to simply pass the filename as argument, and open it yourself. Like many other unix command line tools.

Comment on Re: Testing <> Download Code

Replies are listed 'Best First'.
Re^2: Testing <> by Anonymous Monk on Oct 03, 2011 at 15:35 UTC
That works for `/tmp/>echo "hello world\n" \| myscript` [download] and now called on its own doesn't hang `/tmp/>myscript` [download] but there again its not clear how a usage message could be printed out. But it now fails when passed a filename `/tmp/>cat x October 2011 S M Tu W Th F S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 /tmp/myscript x` [download] it doesn't print the contents of the file :-( Isn't there a simpler solution? I thought that this would have a simple, forehead slapping, solution.	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^2: Testing <>
by Anonymous Monk on Oct 03, 2011 at 15:35 UTC

/tmp/>echo "hello world\n" | myscript
[download]

/tmp/>myscript
[download]

But it now fails when passed a filename

/tmp/>cat x
   October 2011
 S  M Tu  W Th  F  S
                   1
 2  3  4  5  6  7  8
 9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30 31
/tmp/myscript x
[download]

[reply]
[d/l]
[select]