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This article needs additional citations for verification. (October 2017)
|Original author(s)||AT&T Bell Laboratories|
|Developer(s)||Various open-source and commercial developers|
|Initial release||February 1973|
|Operating system||Unix, Unix-like, Plan 9, Inferno, KolibriOS, IBM i|
|License||Plan 9: MIT License|
In most Unix and Unix-like operating systems, the
ps program (short for "process status") displays the currently-running processes. A related Unix utility named
top provides a real-time view of the running processes.
KolibriOS includes an implementation of the
ps command. The ps command has also been ported to the IBM i operating system. In Windows PowerShell,
ps is a predefined command alias for the
Get-Process cmdlet, which essentially serves the same purpose.
# ps PID TTY TIME CMD 7431 pts/0 00:00:00 su 7434 pts/0 00:00:00 bash 18585 pts/0 00:00:00 ps
$ ps -A | less
$ # Trying to find the PID of `firefox-bin` which is 2701 $ ps -A | grep firefox-bin 2701 ? 22:16:04 firefox-bin
The use of
pgrep simplifies the syntax and avoids potential race conditions:
$ pgrep -l firefox-bin 2701 firefox-bin
To see every process running as root in user format:
# ps -U root -u USER PID %CPU %MEM VSZ RSS TT STAT STARTED TIME COMMAND root 1 0.0 0.0 9436 128 - ILs Sun00AM 0:00.12 /sbin/init --
|%CPU||How much of the CPU the process is using|
|%MEM||How much memory the process is using|
|ADDR||Memory address of the process|
|C or CP||CPU usage and scheduling information|
|COMMAND*||Name of the process, including arguments, if any|
|PID||Process ID number|
|PPID||ID number of the process's parent process|
|PRI||Priority of the process|
|RSS||Resident set size|
|S or STAT||Process status code|
|START or STIME||Time when the process started|
|VSZ||Virtual memory usage|
|TIME||The amount of CPU time used by the process|
|TT or TTY||Terminal associated with the process|
|UID or USER||Username of the process's owner|
|WCHAN||Memory address of the event the process is waiting for|
* = Often abbreviated
ps has many options. On operating systems that support the SUS and POSIX standards,
ps commonly runs with the options -ef, where "-e" selects every process and "-f" chooses the "full" output format. Another common option on these systems is -l, which specifies the "long" output format.
Most systems derived from BSD fail to accept the SUS and POSIX standard options because of historical conflicts. (For example, the "e" or "-e" option will display environment variables.) On such systems,
ps commonly runs with the non-standard options aux, where "a" lists all processes on a terminal, including those of other users, "x" lists all processes without controlling terminals and "u" adds a column for the controlling user for each process. For maximum compatibility, there is no "-" in front of the "aux". "ps auxww" provides complete information about the process, including all parameters.
- Task manager
- kill (command)
- List of Unix commands
- nmon — a system monitor tool for the AIX and Linux operating systems.
- pstree (Unix)
- top (Unix)
- McElhearn, Kirk (2006). The Mac OS X Command Line: Unix Under the Hood. John Wiley & Sons. ISBN 978-0470113851.
- Shotts (Jr), William E. (2012). The Linux Command Line: A Complete Introduction. No Starch Press. pp. 96–98. ISBN 9781593273897. Retrieved 16 October 2017.
- The Single UNIX Specification, Version 4 from The Open Group – Shell and Utilities Reference,
- Plan 9 Programmer's Manual, Volume 1 –
- Inferno General commands Manual –
- Show all running processes in Linux using ps command
- In Unix, what do the output fields of the ps command mean?