How do you get current CPU utilization, memory and disk space usage in Linux/Unix?

What are the commands?

1. quota

   All are allocated a certain amount of disk space on the file system for their personal files, usually about 100Mb. If you go over your quota, you are given 7 days to remove excess files.

   To check your current quota and how much of it you have used, type

   % quota -v

   df

   The df command reports on the space left on the file system. For example, to find out how much space is left on the fileserver, type

   % df .

   du

   The du command outputs the number of kilobyes used by each subdirectory. Useful if you have gone over quota and you want to find out which directory has the most files. In your home-directory, type

   % du

2. use prstat
3. For CPU utilization "top" can be used.

thanks to http://www.geekinterview.com/question_details/61146