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Best method to capture return code from system calls?

by bwelch (Curate)
on Aug 24, 2005 at 14:25 UTC ( #486200=perlquestion: print w/replies, xml ) Need Help??

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  1. or download this
    use strict;
    system( "cp /analysis/fasta1.fa /analysis2/fasta1.fa" ) 
        or die print "Can't copy fasta file: $! \n";
    
  2. or download this
    use strict;
    &doSystemCommand(  "cp /analysis/fasta1.fa /analysis2/fasta1.fa"  );
    ...
            die "Failed executing [$systemCommand]\n"; 
        }
    }
    

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Node Type: perlquestion [id://486200]
Approved by willyyam
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[Eily]: you could tie a variable into not having the same value each time, if you like to make people who try to debug your code facepalm
[Corion]: perl -wle 'package o; use overload q("") => sub {warn "str"; ""}, bool => sub{warn "bool"; 1}; package main; my $o={}; bless $o => o; print "Yay" if ($o && !length($o))'
[Corion]: But people writing such code should document the objects they construct and why it makes sense for an object to be invisible as string while being true in a boolean context
[hippo]: That's equal parts clever and horrendous.
[Eily]: the overload version wouldn't return true with "$x" && !length $x though, I guess
[hippo]: The more I look at this code, the more $x is a plain old scalar and the more this condition will never be true. I'm calling it a bug at this point.
[hippo]: Thanks for your input which has soothed my sanity (a little)
[Corion]: Eily: Sure - if you force both things into stringy things, then you break that magic. But that would also mean that you changed the expression, as now $x = 0.00 will be true instead of false as it were before
[Corion]: Ah no, at least in my feeble experiments that doesn't change the meaning
[Corion]: We sell sanity in small packages ;)

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