This set of instructions is intended to be a step by step, copy/paste walkthrough of the process.

Open a Terminal instance with the root user
Switch to directory where you want to work from, I will be using my user’s pre-existing downloads folder
cd /~/downloads
Connect and download the Intelligent Updater script:
ftp ftp.symantec.com
You will be prompted for a user name
anonymous
press: Enter
When asked for password
press: Enter
Navigate to the definition repository
cd AVDEFS/symantec_antivirus_corp/
Locate the file to download
ls *unix*

The file name will have the format of YYYYMMDD-REV-unix.sh. Example: 20090826-009-unix.sh (describing definitions for the 26th of August 2009, revision 009)
Please note that for each definition revision there will be a 32 bit and a 64 bit version
Throughout the rest of this walkthrough I will refer to the file that you choose in this step as ‘<filename>’

Download the file
get <filename>
Disconnect from the FTP server after the transfer is complete:
bye
press: Enter
modify permissions to make file executable
chmod 555 <filename>
To unpack and apply the definitions that you just downloaded:
./<filename>
To query the current installed definition date:
/opt/Symantec/symantec_antivirus/sav info –d



Technical Information

Note: Linux commands are case sensitive.
Note: By default, the Definition Watcher Quick Scan must complete before the current date will be displayed; please allow a few minutes for this process to complete.
Note: The Intelligent Updater will only copy new definitions to the virusdefs/incoming folder. To finish processing these new definitions the rtvscan daemon must be running.

This script can be downloaded from following locations:

ftp://ftp.symantec.com/AVDEFS/symantec_antivirus_corp/

http://www.symantec.com/business/security_response/definitions/download/detail.jsp?gid=savce