Back up logs file and create a script showing the backed up logs and the running logs
 

Hi
Hope I'm through to the right section.

I want to create a bash script that pulls logs from a back up file so I would be able to compare the running logs against the backed up logs to see if a "bad" guy has messed around with the system. The logs I want to use are /var/log/messages and /var/log/boot.log. Is this possible?

If not I just want to create a good script serving good use to a security admin

Everything is "possible", even windows may one day turn into a good OS, ( nah! )
But first post what you have already tried no one here is going to write the script for you, second if you are just starting out with shell scripting grab a copy of the advanced bash scripting guide ( abs ), it covers the basic's right upto advanced stuff.

Tell us what have you tried so far, we can try suggesting the fix if there are issues but we cant serve cooked recipes.

right what I want to do now is log any errors in the var/log/messages, the command I am using is

logrobot /var/log/messages 60 'error' 'panic' -show 5 10

logrobot command is not there, is there any command similar to this?

Maybe install it? http://www.logrobot.com/

I know you can install it, I just wanted to know if there is a command similar to it where I dont have to install it