Ps (Unix)

Template:Short description Template:Multiple issues Template:Infobox software In most Unix and Unix-like operating systems, the ps (process status) program displays the currently-running processes. The related Unix utility top provides a real-time view of the running processes.

Implementations

KolibriOS includes an implementation of the Template:Code command.<ref>Template:Cite web</ref> The Template:Mono command has also been ported to the IBM i operating system.<ref>Template:Cite web</ref> In Windows PowerShell, ps is a predefined command alias for the Get-Process cmdlet, which essentially serves the same purpose.

Examples

<syntaxhighlight lang="console">

1. 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 </syntaxhighlight>

Users can pipeline ps with other commands, such as less to view the process status output one page at a time:

<syntaxhighlight lang="console"> $ ps -A | less </syntaxhighlight>

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:<syntaxhighlight lang="console"> $ # Trying to find the PID of `firefox-bin` which is 2701 $ ps -A | grep firefox-bin 2701 ? 22:16:04 firefox-bin </syntaxhighlight>

The use of pgrep simplifies the syntax and avoids potential race conditions: <syntaxhighlight lang="console"> $ pgrep -l firefox-bin 2701 firefox-bin </syntaxhighlight>

To see every process running as root in user format: <syntaxhighlight lang="console">

1. 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 -- </syntaxhighlight>

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 from X/Open System Interfaces (XSI), an optional extension to POSIX.

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.

See also

• Task manager
• kill (command)
• List of Unix commands
• nmon – a system monitor tool for AIX and Linux operating systems
• pstree (Unix)
• lsof

Further reading

• Template:Cite book
• Template:Cite book

External links

• Template:Man
• Template:Man
• Template:Man
• Show all running processes in Linux using ps command
• In Unix, what do the output fields of the ps command mean?