matiu@speedy:~/tmp/qt$ sudo update-alternatives --remove-all     /usr/bin/assistant assistant "/usr/bin/assistant-qt4" "40"     --slave /usr/share/man/man1/assistant.1.gz assistant.1.gz     "/usr/share/man/man1/assistant-qt4.1.gz"
update-alternatives: error: unknown argument `assistant'
matiu@speedy:~/tmp/qt$ sudo update-alternatives --remove-all     /usr/bin/assistant 
update-alternatives: error: no alternatives for /usr/bin/assistant.