in reply to Program unsuspectingly dies with no reason why. -FIXED!

Here are the relevant lines: 

        &clean_the_file();

sub clean_the_file {
        my ( $sourcefile, $removeq ) = @_;
        `grep -v $removeq $sourcefile > $tempfile`;
}

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You're calling clean_the_file with no arguments, and passing those (no) arguments on to grep, which is going to hang waiting for input.

That's my guess.

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Re^2: Program unsuspectingly dies with no reason why.
by misconfiguration (Sexton) on Feb 13, 2008 at 21:21 UTC
    I think I'm going to have to agree with Kyle. Does anyone think I should remove the grep -v function from backticks and have Perl handle it with the system(); call? I think I'm going to try it this way, so far not much luck with the issue. Thanks for all of the replies so far!
[reply]

      Backticks are for when you want to capture the output of some shell command. In this case, you're redirecting output to a file, so backticks won't do that. Your backticks also don't give you anything in a void context.

      That said, putting the same thing in system won't help either. It's the underlying grep that's hanging.

      I think that grep needs to get some arguments. You could do this, minimally: 

      `grep -v $removeq $sourcefile /dev/null /dev/null > $tempfile`;

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      That won't hang, but it also won't work until $removeq and $sourcefile are right. You probably ought to be passing them in initially: 

      &clean_the_file( $sourcefile, $removeq );

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      I can't tell what $sourcefile should be, though.

      Hope this helps.

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        Well so far, even after passing those elements to the subprocess call "&clean_the_file();" I still had no luck. Albeit, I did remember reading about subprocess' being named with funky underscores causing issues with Perl awhile back. This may not be the case, but I removed the name of the sub() function renamed it to cleanthefile();.

        I commented everything out and just printed my variables $sourcefile and $removeq, $sourcefile prints the directory name as expected, BUT - $removeq spits this output out 
        [root@oailxpp02 ccsys]# /root/mkpq -r queue-04
Global symbol "$removeq" requires explicit package name at /root/mkpq 
+line 87.
Execution of /root/mkpq aborted due to compilation errors.

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        My guess is: the scalar isn't being handled properly, the subprocess can't bring it into it's set of instructions, am I on the right track? Does anyone have any recommendations?
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      I think you missed Kyle's point. Using system instead of backticks to call grep should not matter here.

      To illustrate Kyle's point, add these lines just before your grep line: 

      print "removeq = $removeq\n";
print "sourcefile = $sourcefile\n";

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      I suspect these variables will not contain what you expect them to.

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