Well I have installed avast anti virus on Ubuntu 12.04. But after updating, it crashes! So I have made some tweaks like below:

1. Press Ctrl+Alt+T to open the Terminal. When it opens, run the command below.

   sudo gedit /etc/init.d/rcS
   

2. Type your password and hit Enter.

3. When the text file opens, add the line:

   sysctl -w kernel.shmmax=128000000
   

4. Make sure the line you added is before:

   exec /etc/init.d/rc S
   

5. This is what it should look like:

   #! /bin/sh
   
   # rcS
   
   #
   # Call all S??* scripts in /etc/rcS.d/ in numerical/alphabetical order
   #
   
   sysctl -w kernel.shmmax=128000000
   
   exec /etc/init.d/rc S
   

6. Save the file.

7. Reboot.

My question is: Did I do anything wrong? I mean as I have made some tweaks, will it lower the security of Avast down like viruses do? Please if you are a programmer check this if it contains bug or harmful intentions... Thanks.