Here are known applications which support the French Republican calendar:
Perl DateTime::Calendar::FrenchRevolutionary
On Gentoo, install the perl dependencies:
emerge --ask dev-perl/Params-Validate
emerge --ask dev-perl/DateTime
Or install the perl modules manually:
# cpan
cpan[4]> install "Params::Validate"
# cpan /frenchrevolutionary/
Then you can print the current date:
perl -MDateTime::Calendar::FrenchRevolutionary -le 'print DateTime::Calendar::FrenchRevolutionary->now->strftime("%c")'
