Two issues:pf -fU <user> not showing particular user processes while ps -ef | grep <user> or  ps aux can.pstree -p <pid>, where pid is that particular process I mentioned above, can give output of the child processes while ps -ef | grep <childpid> doesn't show any.  And thisweird behavior is seen only for processes related to this particular sge service which was started using service command and not for any other processes.[root@myserver ~]# ps -fU sgeadminUID        PID  PPID  C STIME TTY          TIME CMD[root@myserver ~]# ps -ef | grep sgeadminsgeadmin  1754     1  0 Jan21 ?        00:16:36 /ge2011.11/bin/linux-x64/sge_execdroot      4097  3982  0 18:52 pts/0    00:00:00 grep sgeadminsgeadmin 27248     1  0 16:59 ?        00:00:03 /ge2011.11/bin/linux-x64/sge_qmaster[root@myserver ~]# pstree -paA 27248sge_qmaster,27248  |-{sge_qmaster},27255  |-{sge_qmaster},27256  |-{sge_qmaster},27257  |-{sge_qmaster},27258  |-{sge_qmaster},27263  |-{sge_qmaster},27264  |-{sge_qmaster},27265  |-{sge_qmaster},27266  |-{sge_qmaster},27267  |-{sge_qmaster},27268  |-{sge_qmaster},27269  `-{sge_qmaster},27289[root@myserver ~]# ps -ef | grep -E '27255|27256|27257|27258|27263|27264|27265|27266|27267|27268|27269|27289'root      4274  3982  0 18:53 pts/0    00:00:00 grep -E 27255|27256|27257|27258|27263|27264|27265|27266|27267|27268|27269|27289[root@myserver ~]#So I tried starting other processes and it's working:myserver @ /homes/sgeadmin : sleep 1000 &[1] 4528myserver @ /homes/sgeadmin : ps -fU sgeadminUID        PID  PPID  C STIME TTY          TIME CMDsgeadmin  4482  4481  0 18:57 pts/0    00:00:00 -tcshsgeadmin  4528  4482  0 18:57 pts/0    00:00:00 sleep 1000sgeadmin  4529  4482  0 18:57 pts/0    00:00:00 ps -fU sgeadminmyserver @ /homes/sgeadmin : exitlogout[root@myserver ~]# ps -fU sgeadminUID        PID  PPID  C STIME TTY          TIME CMDsgeadmin  4528     1  0 18:57 pts/0    00:00:00 sleep 1000[root@myserver ~]#Edit 1:Okay, ps -fu <username> gives output. It seems the difference is there in real user id and effective userid. Yes, root is the real user in this case.But any explanation for the second issue? pstree showing the child processes while ps -ef doesn't?Edit 2:Okay, it is something to do with TGID. 
Can someone explain this weird ps behavior?
process;services;ps;uuid
This answers it clearly: https://stackoverflow.com/questions/9305992/linux-threads-and-processHere in my case, all the child processes displayed are threads and hence, can't be seen in ps -ef output but only pstree.  