Re^3: invoke shell with `` failed

following is my script for space detect here the dir is: "/slowfs/hspice01/liguoj/performance/MT4/Rundir/Tue/RHEL4", and will not change during runtime.
detect_disk() will invoke many times, the problem is during the first several times it run correct, but then failed.

sub detect_disk
{
    my ($flag, $dir) = @_; 
    my $available_space = `df $dir`;
    my @array = split(/\s+/, $available_space);
    $available_space = $array[10];

    if ($flag eq 'entry' and $available_space < 6000000)
    {   
        print ("NOTICE: The left space of $dir is $available_space (KB
+), please make sure enough space is available for the regresssion.\n\
+n");
    }   
    elsif ($flag eq 'routine' and ($available_space < 1000000))
    {   
        print ("NOTICE: The left space of $dir is $available_space (KB
+), regression will waiting!\n");
        sleep 60; 
        while ($available_space < 1000000)
        {
            # send_mail($mail_list, $report_title, $report_file);
            $available_space = `df $dir`;
            @array = split(/\s+/, $available_space);
            $available_space = $array[10];
            sleep 60; 
        }
    }   
}
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Re^4: invoke shell with `` failed by Porculus (Hermit) on Apr 15, 2009 at 08:38 UTC
After some experimentation, I've managed to duplicate this error message -- but (on my system) it only happens when `$dir` is more than about two megabytes long! Are you sure `$dir` never changes? The error is coming from the operating system; it can't be trapped with `eval` like I'd expected. However, you can determine whether the command succeeded by checking `$?`, which will be 0 if it worked and something else if it didn't. So I suggest what you do is change your code slightly: my $available_space = `df $dir`; if ($? != 0) { warn "df failed: command was `df $dir`"; } [download] (and the equivalent in the other place where you use ``). That should tell you exactly what is being considered "too long".	[reply] [d/l] [select]

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Re^4: invoke shell with `` failed
by Porculus (Hermit) on Apr 15, 2009 at 08:38 UTC

After some experimentation, I've managed to duplicate this error message -- but (on my system) it only happens when $dir is more than about two megabytes long! Are you sure $dir never changes?

The error is coming from the operating system; it can't be trapped with eval like I'd expected. However, you can determine whether the command succeeded by checking $?, which will be 0 if it worked and something else if it didn't. So I suggest what you do is change your code slightly:

my $available_space = `df $dir`;
if ($? != 0) {
    warn "df failed: command was `df $dir`";
}
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(and the equivalent in the other place where you use ``).

That should tell you exactly what is being considered "too long".

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