This page contains some useful commands for managing the different Nepomuk processes

Restarting Nepomuk

$ qdbus org.kde.NepomukServer /nepomukserver quit
wait for it to quit
$ nepomukserver

Restarting any service

If you need to restart any particular service -

$ qdbus org.kde.nepomuk.services.$SERVICE /servicecontrol shutdown
wait for it to quit
$ nepomukservicestub $SERVICE

Just killing the service won't work, cause the 'nepomukserver' automatically restarts crashed services.