Why does ps -elf list user number and not user name?

Question

When I do this ps command:

sudo ps -elf | grep firefox

I see this output:

0 S 1002     20214     1  0  80   0 - 269240 poll_s 14:03 ?       00:00:24 /usr/lib/firefox/firefox
0 S jeff     22671 15484  0  80   0 -  3396 pipe_w 15:14 pts/0    00:00:00 grep --color=auto firefox

Why do I see my own user name in one case, but a user number in the other case. The other user is a real person logged into the computer. I can tell who it is by looking at /etc/passwd.

Answer 1

If your username is longer than 8 characters, some tools will show your uidnumber instead of your username.