ClamAV can only detect viruses and move any infected files into a quarantined folder; it cannot remove them from files. ClamAv detects viruses on all platforms, but it is primarily useful for Windows viruses and malware.
ClamTK is the graphical interface for ClamAV, you cannot use ClamTk without having ClamAV installed previously.
Once installed ClamAV will run in the background as a daemon and you can use the ClamTk interface in Linux to interact with it.
The ClamAV database is automatically updated via the running clamav-freshclam daemon started by the /etc/init.d/clamav-freshclam init script, there is no actual need to update it manually.
It is controlled by the /etc/clamav/freshclam.conf with a default configuration of checking for a new database every 1 hour
# Check for new database 24 times a day
Checks 24
DatabaseMirror db.local.clamav.net
DatabaseMirror database.clamav.net
To force update the ClamAV virus database in the terminal you can use the command
sudo freshclam
ClamAV is definitely a good anti virus software, for a list and more information about anti virus for Ubuntu please have a look at any of the following posts
Best Answer
ClamAV is the scanner or deamon.
ClamTk is a GUI front-end for ClamAV using gtk2-perl.
It is common practice in Linux to split the frontend/GUI from the actual program so you can use it on a server install.