ps (Unix)
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|
Cross-platform | |
Type | Command |
---|---|
License | Plan 9: MIT License |
In most
ps
(process status) program displays the currently-running processes. The related Unix utility top
Implementations
ps
is a predefined command aliasGet-Process
cmdlet, which essentially serves the same purpose.
Examples
# 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
Users can pipeline ps
with other commands, such as less to view the process status output one page at a time:
$ ps -A | less
Users can also utilize the ps
command in conjunction with the grep
command (see the pgrep
and pkill
commands) to find information about a single process, such as its id:
$ # 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 --
Header line
Column Header | Contents |
---|---|
%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 |
NI | nice value |
F | Flags |
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
Options
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
See also
- Task manager
- kill (command)
- List of Unix commands
- nmon – a system monitor tool for AIX and Linux operating systems
- pstree (Unix)
- lsof
References
- ^ "Shell - KolibriOS wiki".
- ^ IBM. "IBM System i Version 7.2 Programming Qshell" (PDF). IBM. Retrieved 2020-09-05.
Further reading
- McElhearn, Kirk (2006). The Mac OS X Command Line: Unix Under the Hood. 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.
External links
- 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?