perl -MCPAN -e 'CPAN::Shell->o("conf")'

##</code><code>##

$CPAN::Config options from :
    commit             [Commit changes to disk]
    defaults           [Reload defaults from disk]
    help               [Short help about 'o conf' usage]
    init               [Interactive setting of all options]

    applypatch         undef
    auto_commit        undef
    build_cache        undef
    build_dir          undef
    build_dir_reuse    undef
    build_requires_install_policy undef
    bzip2              undef
    cache_metadata     undef
    check_sigs         undef
    colorize_debug     undef
    colorize_output    undef
(...)