Process state codes in ps output

The output of the ps command shows a letter for the process state (depending on the output format you've asked ps to use, it may or may not be shown).

An example ps output (with most lines snipped for brevity):

[davidp@supernova:~]$ ps u
davidp    3995  0.0  0.4   3324  1956 pts/2    Ss   Aug17   0:00 /bin/bash
davidp   25049  0.0  0.8   7104  3908 pts/5    S+   Aug19   0:10 irssi
davidp   26180  0.0  0.1   2656   908 pts/0    R+   14:41   0:00 ps u

The 'STAT' column shows the state codes for each process.

Process state codes

The codes used are:

Code Meaning
D Uninterruptible sleep (usually IO)
R Running or runnable (on run queue)
S Interruptible sleep (waiting for an event to complete)
T Stopped, either by a job control signal or because it is being traced.
W paging (not valid since the 2.6.xx kernel)
X dead (should never be seen)
Z Defunct (“zombie”) process, terminated but not reaped by its parent.

For BSD formats and when the stat keyword is used, additional characters may be displayed:

Code Meaning
< high-priority (not nice to other users)
N low-priority (nice to other users)
L has pages locked into memory (for real-time and custom IO)
s is a session leader
l is multi-threaded (using CLONE_THREAD, like NPTL pthreads do)
+ is in the foreground process group


linux/psflags.txt · Last modified: 2010/02/26 10:45 (external edit)
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