PS(1)
NAME
ps − process status
USAGE
ps [ options ]
DESCRIPTION
Ps prints information about processes. Normally, only processes started by you are candidates to be printed by ps. However, some of the options below can change this, causing other users’ processes to be candidates to be printed or including processes without control terminals in the candidate pool.
All output formats include, for each process, the process ID (PID), CPU time used by the process (TIME), the state (STAT) of the process, and an indication of what command (COMMAND) is running.
The state appears as a sequence of two letters, e.g., RN. The first letter indicates the runnability of the process: R for runnable processes, T for stopped processes, and S for those sleeping. The second letter indicates whether a process is running with altered CPU scheduling priority, as under nice(1). If the process priority is reduced, an N is shown; if the process priority has been artificially raised, then a less-than character (<) is shown. Processes running without special treatment have just a blank.
OPTIONS
The various options that you can use with ps are described below. A second argument is taken to be the file containing the system’s namelist. A third argument is interpreted as the name of a swap file to use.
a Request information about all processes with terminals.
c Print the command name, as stored internally in the system for accounting purposes, rather than the command arguments, which are kept in the process’ address space. This is more reliable, if less informative, since the process is free to destroy the latter information.
g Ask for all processes. Without this option, ps only prints “interesting” processes. Processes are deemed to be uninteresting if they are process group leaders. This normally eliminates top-level command interpreters and processes waiting for users to log in on free terminals.
l Print a long listing, with fields PPID, CP, PRI, NI, ADDR, and SIZE as described below.
u Produce user-oriented output, including the USER, NICE, and SIZE fields as described below.
v Produce a version of the output containing virtual memory statistics. This includes the PAGEIN, SIZE, LIM, and TSIZ fields as described below.
w Use a wide output format (132 columns rather than 80). If repeated, (e.g., ww), use arbitrarily wide output. This information helps determine how much of long commands to print.
x Ask about all processes, even those with no control terminal.
−N Print the AEGIS name of processes.
# Restrict the output to the process number indicated by the pound sign (#). If you use this option, you must place it at the end of the command line.
VARIABLE OUTPUT FIELDS
Fields that are not common to all output formats are described below.
USERName of the owner of the process.
NICE(or NI) Process scheduling increment. See setpriority(2) for more detail.
SIZEVirtual size of the process (in 1024-byte units).
LIMSoft limit on memory used; specified via a call to setrlimit(2). If no limit has been specified, then the limit is shown as xx.
TSIZSize of text (shared program) image.
PAGEINNumber of disk I/Os resulting from references by the process to pages not loaded in core.
UIDNumerical user-ID of process owner.
PPIDNumerical ID of parent of process.
CPShort-term CPU usage factor (used in scheduling).
PRIProcess priority (nonpositive when in noninterruptible wait).
ADDRAddress space ID of the process
FFlags associated with a process:
SLOAD000001in core
SSYS000002system process - Level 1
STRC000010process is being traced
SKEEP000100another flag to prevent swap out
SNOVM004000no vm, parent in a vfork()
SPAGI 008000 init data space on demand
SPTECHG 100000 pte’s for process have changed
CAUTIONS
While ps makes an educated guess as to the filename and arguments given when the process was created by examining memory or the swap area, this method is inherently somewhat unreliable. In any event, a process is entitled to destroy this information, so the names cannot be counted on too much.
Data can change drastically while ps is running, process information that you get from it is only valid for the moment.