Shell Programming and Scripting

I want to bug and make lag in the vps using commands on linux by a normal user, SSH on centos 6.

Okay - I do not get what you want.

One good definition of vps is simply a kind of virtual container - almost like a separate standalone OS is how it appears inside the container..
If the virtual is configured the way it appears you seem to want, bash will work as you expect there. Like it already does in the host OS.

I assume you want to run something in the container (individual vps) rather than host.

So can you define "bug": do you mean audit? Keylogger?
Also define lag: do you mean slow down?

It also sounds like you have security issues and these solutions are supposed to fix them. Which they very probably will not do.

So what are you trying to do ultimately? - not how you plan to get there.