You could also do this:

use warnings;
no warnings 'uninitialized';
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It's handy, especially in CGI, for situations like if ( $param_this =~ /that/ ) {}, which otherwise has to be if ( $param_this and $param_this =~ /that/ ) {} to avoid the warnings. It's sort of a DWIW kludge but since you're doing comparisons without explicitly checking what sort of thing you're comarping ("e" > 6, for example), it might be fine for what you're doing.