How about using an environmental variable? 

use constant DEBUGGING => $ENV{DEBUGGING} || 0;

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Otherwise, you'll have to wrap your @ARGV processing in a BEGIN {} block so it will run at compile time. That's when (and how) use statements run.

In reply to Re: change 'use constant' value through commandline arguments? by chromatic
in thread change 'use constant' value through commandline arguments? by neuroball

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