Grabbing STDERROR

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

I am trying to get the error message if top fails. Is there a way to grab STDIN & STDERROR in the (my) open statement?

#!/usr/bin/perl
open( CMD, "top -b -n1 |") ||
  die "cannot fork: $!";

while ( <CMD> ) {
        if ( /^top:/ ) {
                print "Detected lrk4 version of top\n";
        }
}
close( CMD );
[download]

Comment on Grabbing STDERROR Download Code

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Re: Grabbing STDERROR by btrott (Parson) on Nov 10, 2000 at 07:23 UTC
Take a look at IPC::Run. I prefer it to IPC::Open3, personally, but that's me. Here's a snippet: `use IPC::Run qw( run ); my($out, $err); my @top = qw( top -b -n1 ); run \@top, \undef, \$out, \$err or die "top returned $?";` [download]	[reply] [d/l]
RE: Re: Grabbing STDERROR by juanvaldez (Initiate) on Nov 10, 2000 at 21:20 UTC
I just wanted to thank the people that replied. I had thought of the shell redirect (2>&1) but forgot the syntax. I am not able to install a module because this will be run on few thousand machines but I am deffinetly going to take a look at IPC::Open3. And before I forget the shell redirect did work like a charm!	[reply]
RE: Grabbing STDERROR by AgentM (Curate) on Nov 10, 2000 at 07:16 UTC
IPC::Open3 is exactly what you're looking for! AgentM Systems nor Nasca Enterprises nor Bone::Easy nor Macperl is responsible for the comments made by AgentM. Remember, you can build any logical system with NOR.	[reply]
Re: Grabbing STDERROR by extremely (Priest) on Nov 10, 2000 at 06:59 UTC
In some shells you can add `2>&1` before the pipe and get both STDERR and STDOUT on STDOUT... -- $you = new YOU; honk() if $you->love(perl)	[reply]

AgentM Systems nor Nasca Enterprises nor Bone::Easy nor Macperl is responsible for the comments made by AgentM. Remember, you can build any logical system with NOR.