top won't run from the commandline with &, so it's not surprising that perl can't do it either.

Are you trying to gather system statistics? If you really want to use top, have you tried top's batch mode (-b option)?

Update: sorry, I thought you were saying 'perl' couldn't run in the background - didn't catch the issue with 'top' until after :-/

What?! This is absolutely false. 'perl' can certainly run in the background!

# perl -e 'print "hello\n"' > test.out 2>&1
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#cat test.out
hello
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"my top command does not execute" is a rather vague problem description. Could you be more specific?

If you're referring to the fact that nothing gets written to top.log, then you're mistaken when you said it runs fine without the "&". You never write anything to that file.

Correction:

use strict;
open (OUT,">top.log") or die "cannot create: $!\n";
for (;;){
    my $top = `top n 1`;
    print OUT $top;
    sleep 10;

}
close OUT;
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Sorry I was actually abbreviating my original script from memory. The script writes and executes top just fine when I don't run it as a background job. The explanation that top does not run as a background job is very helpful. Thank you.

`top -b -n 1`
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I managed to get top to work using the b argument. It's certainly not a Perl issue but it was quite baffling getting it to work properly. Thank you all for leading me in the right direction.

#perl script.pl > script.out 2>&1 &
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