That's what ||= is for. 
$infile ||= "blah";
#this will only set $infile="blah" when $infile is undefined.

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Or there's always 
$infile= ? $infile : "default";

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vroom | Tim Vroom | vroom@cs.hope.edu

In reply to RE: Defaults for command line args by vroom
in thread Defaults for command line args by ChuckularOne

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