To install Plack::Middleware::Debug::W3CValidate, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Plack::Middleware::Debug::W3CValidate
CPAN shell
perl -MCPAN -e shell
install Plack::Middleware::Debug::W3CValidate
For more information on module installation, please visit the detailed CPAN module installation guide.