Read perlrun search for "use module"

Files are where it's at :) oneliners get unwieldy pretty quick  perl -le ' use Data::Dump; dd [6..9]; '

OTOH, it could be as simple as perl -MToolkit -e ' dd \@INC '

or even

export PERL5OPT=-MData::Dump -CSD 
perl  -e ' dd\%INC '