I'my attempting to call an program inside perl, and get its stdout: 
my $result = `blastall -i foo -o bar -p blastx -d baz`;

if ($!) {
  die "something bad happened: $!";
}

[download]

However, the program always die, even if blastall seems to be working properly. It seems that $! only stores something stderr, but not always critical.

So, how should I get the return value properly? Should I use: 

eval {
  $result = `......`;
}
if ($@) {
  die "......";
}

[download]
instead?

In reply to Capture external program return value by llancet

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