Ping loop doesn't print

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

The script below pings as expected, but it /never/, /ever/, prints anything. Why?

#!/usr/bin/perl
use strict;
use warnings;
use Net::Ping;

my $i = $ARGV[0] || -1;
while(--$i){
        my $p = Net::Ping->new();
        my $host = int(rand(255)) . '.' . int(rand(255)) . '.' . int(r
+and(255)) . '.' . int(rand(255));
        $p->ping($host) and print "\n$host lives!\n";
        $p->close();
        print ".";
}
[download]

Comment on Ping loop doesn't print Download Code

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Re: Ping loop doesn't print by Joost (Canon) on Jun 01, 2007 at 21:10 UTC
suffering from buffering? `#!/usr/bin/perl use strict; use warnings; use Net::Ping; $\|=1; # note this line my $i = $ARGV[0] \|\| -1; while(--$i){ my $p = Net::Ping->new(); my $host = "127.0.0.1"; # for testing purposes $p->ping($host) and print "\n$host lives!\n"; $p->close(); print "."; }` [download] See perlvar's entry on `$\|` "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l] [select]
Re: Ping loop doesn't print by MidLifeXis (Monsignor) on Jun 01, 2007 at 21:08 UTC
You need to either print to STDERR, or set STDOUT to non buffering. `select(STDOUT); $\|++;` [download] update: As far as never printing, much of the IP space is vacant, invalid, or unresponsive. --MidLifeXis	[reply] [d/l]
Re^2: Ping loop doesn't print by Anonymous Monk on Jun 01, 2007 at 21:19 UTC
Thanks.	[reply]