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Re: Re: Re: Re: Re: system & shell metacharacters

by vek (Prior)
on Jul 23, 2003 at 18:14 UTC ( #277288=note: print w/ replies, xml ) Need Help??


in reply to Re: Re: Re: Re: system & shell metacharacters
in thread system & shell metacharacters

Using || die is fine as long as parens are used.

open(FOO, $file) || die "Couldn't open $file - $!\n";

When no parens are present, you should use or die instead.

Personally, I always use parens everywhere so my code is littered with || dies.

-- vek --


Comment on Re: Re: Re: Re: Re: system & shell metacharacters
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|| die or or die :)
by snax (Friar) on Jul 23, 2003 at 20:00 UTC
    I'm just surprised that I've never seen a problem using it exactly as I've written it above, which I do with great regularity. The docs say that the calling signatures are
    open FILEHANDLE, EXPR
    and
    open FILEHANDLE
    My syntax falls into the first case, but what constitutes an "EXPR"? I've got a string, the || operator, then the die -- does that qualify as an EXPR? I'll have to poke around the docs some more.....

    Oh. Playing around with the right and wrong way shows me that my "|| die" syntax fails without die-ing.

      I've got a string, the || operator, then the die -- does that qualify as an EXPR?
      Yes, it does (as you seem to have discovered): since || is higher precedence than the comma, it's parsed roughly as open ( FILEHANDLE, ("filename" || die( ...) ) ); Since your string is always true, the die is never reached.



      If God had meant us to fly, he would *never* have given us the railroads.
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