| The ps
(process status) command is used to list the processes currently
running on the system. This is normally done if a process is taking
too long or appears to have stopped as indicated by a terminal window
not responding or "hanging." By listing the processes,
you can see the name of the command or program that initiated the
process plus any child processes it may have spawned. By executing the
ps
command more than once, you can see if a process is still running by
looking at the time for the process, which is the amount of CPU
time the process is using. If the amount of time does not increase,
then the process may have stopped. You can use the ps
command to check the process ID (PID) of the process and then
"kill" the process if it is taking too long or has
stopped.
The output of the ps
command will display the PID number and the command or program
associated with it. The PID number is normally used to terminate a
process. There are three main options with the ps
command: -e (every process), -f (full listing) and -u
(user). 
| Command Format: |
| ps [-options] |
ps
- The ps
command by itself will display PID, TTY (terminal type), TIME (cpu
time), and CMD (command that initiated the process) for only your
processes running in the current shell. If you opened a terminal
window under CDE, you will not see any of the other processes you have
initiated.
ps -e
- The ps
command with the -e (every) option will display PID, TTY TIME,
and CMD for all process running on the system.
ps -f
- The ps
command with the -f (full) option will show a listing of all
information (UID, PID, PPID, C, STIME, TTY TIME and CMD) but only for
those processes running under the current shell or terminal window.
ps -u
userid - The ps
command with the -u option will display PID, TTY TIME, and CMD
for every processes running on the system for a particular user.
Figure
shows the output of the basic ps
command with no options. The ps
-ef command will show
every process on the system and all information available in a full
listing. Because of the number of processes usually running on a
system, it is useful to pipe the ps
-ef command to more so
that the output can be read a page at a time, as shown in the example
in Figure .
Note that root initiated the /etc/init daemon as process number
1. User aster with PID 1292 is running a Korn shell (-ksh) process
from the console. User rose with PID 1400 is running a clock program
under open windows. Figure
describes the column headings from the ps
-ef command. The
controlling terminal for system daemons appears as a question mark
(?). The word <defunct> will appear in the CMD column if
a process is a zombie or defunct process. In addition,
the CPU time may be a bit higher for a defunct process than for other
processes.
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