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$ perl -MO=Concise,-exec -e'print if $a' 1 <0> enter ... 7 <@> print vK 8 <@> leave[1 ref] vKP/REFC -e syntax OK
$ perl -MO=Concise,-exec -e'if ($a) { print }' 1 <0> enter ... 7 <@> print vK 8 <@> leave[1 ref] vKP/REFC -e syntax OK