I recall doing something like this before, however you might want to have a look at the O'Reilly book "Programming Perl". I think there was a section on using exec|system and evaluating the return values.

my @args = ("/usr/bin/mt", "-f", "$$machine{tape}", "online");

my $status = system(@args) / 256;

if( $status < 0 || $status > 0 ) { &error_code; }
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