[ITT] Perl tricks/idioms

I'll start:

my $buffer = "";
open my $fh, ">", \$buffer or die;

will let you treat $fh as a real filehandle

--

you can use ;__; as a spacer/indicator for bad code

--

&{{
    derp    =>  sub { print "test" },
    herp    =>  sub { print "yes!" },
}->{$ARGV[0] or 'herp'}}

--

keep em coming

use v6;

Only with supported interpreter/compiler versions. Improves all aspects of the language.