Tty tells you the terminal in which the process runs

TTY
tells
you the terminal in which the process runs. The command
tty
will
display the name of your terminal.
TIME
tells you the CPU time used by
the process.
CMD
shows the command that was used to invoke the
process.
ps
has many options. One often used is
-f
. With this option more
information will be displayed:
hong:~ $ps -f
UID PID PPID C STIME TTY TIME CMD
xie 31587 31586 0 21:43 pts/0 00:00:00 -bash
xie 31604 31587 0 21:52 pts/0 00:00:00 ps -f
hong:~ $
in the above example,
UID
shows the user that created the
process.
PPID
is the parent PID.
STIME
is the starting time of the
process.
Another useful option is
-l
:
hong:~ $ps -l
F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY
TIME CMD
000 S 1002 31587 31586 0 72 0 - 502 wait4 pts/0
00:00:00 bash
000 R 1002 31611 31587 0 76 0 - 795 - pts/0
00:00:00 ps
hong:~ $

in this example,
S
tells you the process state:
S
for sleep,
R
for
running,
T
for stopped,
Z
for zombie or defunct processes.
UID
shows
you the User ID number of the user who created the process. In Unix,
each user has a username (such as
xie
in above example) and a integer
uid (such as 1002 for user
xie
, and 0 for root).
PRI
tells you the
scheduling priority of the process. It is between 0 (high) and 127
(low).
NI
is the nice value , which is used to change the priority
indirectly. The nice value is between -20 (a greater chance of a higher
priority) and 19 (a greater chance of lower priority).
To display all processes, use option
-e
. You can combine different
options together:
hong:~ $ps -el
F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY
TIME CMD
100 S 0 1 0 0 68 0 - 104 do_sel ?
00:00:12 init
040 S 0 2 1 0 69 0 - 0 contex ?
00:00:00 keventd
040 S 0 3 1 0 78 19 - 0 ksofti ?
00:00:00 ksoftirqd
040 S 0 4 1 0 69 0 - 0 kswapd ?
00:01:22 kswapd
040 S 0 5 1 0 69 0 - 0 bdflus ?
00:00:00 bdflush
040 S 0 6 1 0 69 0 - 0 kupdat ?
00:00:17 kupdated
040 S 0 7 1 0 69 0 - 0 jfsIOW ?
00:00:00 jfsIO
040 S 0 8 1 0 69 0 - 0 jfs_la ?
00:00:00 jfsCommit
040 S 0 9 1 0 69 0 - 0 jfs_sy ?
00:00:00 jfsSync
140 S 1 63 1 0 69 0 - 347 do_pol ?
00:00:00 rpc.portm
040 S 0 69 1 0 69 0 - 445 do_sel ?
00:03:25 syslogd
140 S 0 72 1 0 69 0 - 327 do_sys ?
00:00:00 klogd
140 S 0 74 1 0 68 0 - 443 do_sel ?
00:18:34 inetd
140 S 0 77 1 0 69 0 - 684 do_sel ?
00:01:05 sshd
040 S 0 86 1 0 69 0 - 332 do_pol ?
00:00:00 rpc.rquot
140 S 0 88 1 0 69 0 - 0 svc_re ?
00:00:00 nfsd
040 S 0 90 1 0 69 0 - 0 svc_re ?
00:00:00 nfsd
040 S 0 89 1 0 69 0 - 0 svc_re ?
00:00:00 lockd
040 S 0 91 89 0 69 0 - 0 rpciod ?
00:00:00 rpciod
040 S 0 92 1 0 69 0 - 0 svc_re ?
00:00:00 nfsd

040 S 0 93 1 0 69 0 - 0 svc_re ?
00:00:00 nfsd
040 S 0 94 1 0 69 0 - 0 svc_re ?
00:00:00 nfsd
040 S 0 95 1 0 69 0 - 0 svc_re ?
00:00:00 nfsd
040 S 0 96 1 0 69 0 - 0 svc_re ?
00:00:00 nfsd
040 S 0 97 1 0 69 0 - 0 svc_re ?
00:00:00 nfsd
040 S 0 100 1 0 69 0 - 341 do_pol ?
00:00:00 rpc.mount
140 S 0 103 1 0 69 0 - 347 do_sel ?
00:00:00 rpc.statd
140 S 0 105 1 0 69 0 - 452 do_sel ?
00:00:00 lpd
040 S 0 107 1 0 68 0 - 339 nanosl ?
00:00:00 crond
040 S 2 110 1 0 69 0 - 339 nanosl ?
00:00:00 atd
140 S 0 121 1 0 68 0 - 821 do_sel ?
00:00:00 httpd
100 S 0 127 1 0 79 19 - 859 nanosl ?
00:00:00 dnetc
000 S 0 131 1 0 69 0 - 449 wait4 ?
00:00:00 RunCache
140 S 99 143 121 0 69 0 - 859 wait_f ?
00:00:02 httpd
140 S 99 144 121 0 69 0 - 852 wait_f ?