CS45 Wednesday lab weeks 5

Some useful utilities for accessing system information

• /proc: /proc is a pseudo file system that provides a file interface to the operating system. Through /proc you can get information about system-wide resource usage and about individual processes running on the system. For example, cat'ing out the /proc files meminfo, swapinfo, loadavg, will give you information about a machine's memory usage, about its swap space usage, and about its cpu load averages.

  Each task has its own subdirecty in /proc containing information about that task. For example:

  $ ps -A
    PID TTY          TIME CMD
   8284 pts/9    00:00:00 tcsh
   9206 pts/9    00:00:00 ps
  $ cd /proc/8284
  $ cat status
  Name:   tcsh
  State:  S (sleeping)
  ...
  				

  See the man page for proc for more information (man 5 proc).

  Also, see documentation with the linux source: linux-2.6.32.44/Documentation/. Different entries in /proc have documentation files in this subdirectory

• top: display information about linux tasks (man top).
• time: can get total wall time, system time and user time for a process' execution.