virus on linux?

[abdelkader belahcene <abelahcene@gmail.com>]

Hi,
I am asking if there is a virus on my machine how to detect it.
the command ps aux  gives all  running processes, all really all? or it may be a hidden process running on background.
Until now, I considered that a virus doen't affect a system if you work as simple user,
and can't damage system without root permission, am I right,  or virus can get root privileges ??
another thing on linux, the program can't run if it not executable, it must have the "x" permission, if we copy a file normally it looses the x permission.
This is what I believe up now, am I right??
thanks for help
bela