So far I've been using nice -n 10, but that's just sets the priority of the command I want to run low, but if there's no other process running at that time the command will take all the remaining cpu power and take as much as it wants. But, is there any command or any way to limit how much processor a command can take? Just as an analogy like in bittorrent I can limit how much bandwidth I want a certain download to take. Thanks. 
Is there any command that limits the use of cpu resources by percentage?
process;cpu;nice;processes
Yes, there are two ways to set hard limits even though not very mainstream since the purpose of the scheduler is to make sure a task completes as fast as possible.CPUlimit, which is not standard in most Linux distributions.Taskset, which allows you to bind a certain application to a specific core. In this second case doesn't specify a percentage but if you have 4 cores, you can bind the application to one core and it will be 25% usage.