In Unix, what do the output fields of the ps command mean?
The ps command varies significantly among Unix
implementations. Each vendor incorporates its own flags and outputs
the results differently. However, most ps variants are
rooted enough in either the System V or BSD syntax that
entering ps -elf (System V) or ps alx (BSD)
will produce something like the following:
F |
S |
UID |
ID |
PPID |
C |
PRI |
NI |
ADDR |
SZ |
WCHAN |
STIME |
TTY |
TIME |
COMD
|
1 |
R |
obiwan |
792 |
779 |
22 |
183 |
20 |
10ec5f80 |
29 |
- |
12:52:24 |
pts/2 |
0:00 |
ps -elf
|
1 |
S |
root |
24621 |
560 |
0 |
154 |
20 |
13603f80 |
11 |
4697c0 |
Jun 16 |
ttyp2 |
0:00 |
telnetd
|
1 |
S |
dvader |
1162 |
1153 |
0 |
154 |
20 |
110a1f80 |
77 |
452be4 |
11:25:41 |
pts/3 |
0:00 |
ssh deathstar
|
This particular example is from HP-UX, whose output is
basically vanilla System V. The following table describes the
meanings of the columns that commonly appear in ps outputs. No
version of ps will display all of these fields, however.
| 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 |
Real memory usage |
S or STAT |
Process status code |
START or STIME |
Time when the process started |
SZ |
Virtual memory usage |
TIME |
Total CPU usage |
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
For information specific to your Unix implementation, consult the
ps man page.
At Indiana University, for personal or departmental Linux or Unix systems support, see At IU, how do I get support for Linux or Unix?
Last modified on August 22, 2008.
