Why does ps aux displays a number instead of a username?

Question

Running ps aux just gave me the following output:

...
www-data 26254  0.0  0.7  27304  3544 ?        S    15:07   0:00 /usr/sbin/apache2 -k start
1001     25807  0.8  0.8  48444  4332 ?        Sl   Sep03 1330:24 ./ts3server_linux_x86
...

www-data is the apach2 user. That's okay, it's what I expected with -u, but what is 1001?

score 24 · Answer 1 · answered Feb 21 '13 at 02:17

24

This can happen if the username is longer than 8 characters.

answered Feb 21 '13 at 02:17

FXL

337

score 3 · Accepted Answer · answered Dec 22 '11 at 16:42

3

It means that user id is 1001 but that id has no name assigned. This can happen for example a command running in a chroot with a user defined in that chroot will not necessarily have a name assigned outside the chroot.

answered Dec 22 '11 at 16:42

ismail

629

score 1 · Answer 3 · answered Dec 22 '11 at 16:41

1

This is most like user's id (uid) for a user which was removed after the process was started. Or perhaps there was some kind of failure resolving username from uid.

answered Dec 22 '11 at 16:41

MK01

151
7

score 1 · Answer 4 · answered Dec 22 '11 at 16:42

1

It is a uid for users whose name is unknown (e.g. an uid missing in /etc/passwd) or perhaps with strange spelling (like maybe Debian-exim, or a user with a long enough user-name, or for a bad entry in /etc/passwd)

answered Dec 22 '11 at 16:42

Basile Starynkevitch

1,176

score 0 · Answer 5 · answered Dec 22 '11 at 16:43

0

It's the user ID. There are cases where Linux doesn't display usernames (this can be a permissions issue). Check out this thread:

http://www.linuxquestions.org/questions/linux-newbie-8/ps-aux-displays-users-as-uids-instead-of-username-645456/

answered Dec 22 '11 at 16:43

Ben D

101
1

Why does ps aux displays a number instead of a username?

5 Answers5