procps/procps-ng

procps is a set of command line and full-screen utilities that provide information out of the pseudo-filesystem most commonly located at /proc.

The following programs are found in procps:

  • free - Report the amount of free and used memory in the system
  • kill - Send a signal to a process based on PID
  • pgrep - List processes based on name or other attributes
  • pkill - Send a signal to a process based on name or other attributes
  • pmap - Report memory map of a process
  • ps - Report information of processes
  • pwdx - Report current directory of a process
  • skill - Obsolete version of pgrep/pkill
  • slabtop - Display kernel slab cache information in real time
  • snice - Renice a process
  • sysctl - Read or Write kernel parameters at run-time
  • tload - Graphical representation of system load average
  • top - Dynamic real-time view of running processes
  • uptime - Display how long the system has been running
  • vmstat - Report virtual memory statistics
  • w - Report logged in users and what they are doing
  • watch - Execute a program periodically, showing output fullscreen

free

  • Report the amount of free and used memory in the system
free
free -m
free -mt
free -gt
Linux will use free RAM for things like disk caching. This artificially elevates the “used” memory figure and reduces the “free” memory figure. The RAM used as disk cache is flagged as both “used” and “available” because it can be very easily reclaimed at any time. In later versions of free there is a more meaningful "available" column that takes these factors into account.

TODO

kill, pkill, pgrep, pmap, ps, pwdx, skill, slabtop, snice, sysctl, tload, uptime, vmstat, w, and watch.