Getting rid of extra outputs

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

Hi Monks,

I need your wisdom again.

I have this script that calls an external program and I realised (after getting malformed header error) that the external program actually output some information. I was told to use the $| = 0 / 1 to stop the malformed header error but now the output is showing on the webpage. Is there a way to ignore the external program's outputs?

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Re: Getting rid of extra outputs by monarch (Priest) on May 27, 2005 at 07:38 UTC
How are you calling the external program? If you are calling it like this my $cmd = 'ls'; my $result = `$cmd`; [download] ..then consider the following approach: my $cmd = 'ls 2>&1'; my $result = `$cmd`; [download] The purpose of the `2>&1` is to take anything output to STDERR and redirect to STDOUT. This will be of no use if your script is on a Win32 machine.	[reply] [d/l] [select]
Re^2: Getting rid of extra outputs by sandrider (Acolyte) on May 27, 2005 at 07:57 UTC
No I don't call it like that. It is a.so file that is called by a.pm module that is provided. I call the external.pm and it calls the external.so file. When I run it via command line I get things like buffering 10000... and then after the results will be returned. I have a feeling that when I do a `use external`, it makes those statements. Is there a work around w/o having to edit external.pm? I don't want to mess about with another persons script.	[reply] [d/l]
Re^3: Getting rid of extra outputs by muntfish (Chaplain) on May 27, 2005 at 11:02 UTC
Seems like you want to temporarily redirect STDOUT to somewhere else? You'll find lots of good stuff if you Super Search here for "redirect stdout" or similar. This is a VERY basic way of doing it, which might get you started: `print "This goes to stdout\n"; { local *STDOUT; open STDOUT, '>/tmp/myoutput'; print "This gets redirected\n"; # more code here that prints stuff to stdout } print "Back to normal stdout\n";` [download] If you really don't need the output of your external.pm then change `/tmp/myoutput` to `/dev/null` (if you're on Unix). Disclaimer: I've never actually used techniques like this in real code, there may be problems/caveats etc. Searching this site should turn up more robust solutions! s^^unp(;75N=&9I<V@`ack(u,^;s\|$.+\`\|"$`$'\"$&\"$"\|ee;/m.+h/&&print$&	[reply] [d/l] [select]