> How to understand kernel PID Understating, I have seen #ps -aux > command show all user process and system process will show, I can't > find Some PID is not there, How can I see Hidden process numbers > > To Find perticular PID > > root ~ # ps -p 100 > PID TTY TIME CMD > root ~ # ps -p 62 > PID TTY TIME CMD > root ~ # > > > please guide me guys, give any idea clues. >
There is *no* hidden process, however a process ID could be consumed by a thread which will be displayed as LWP in ps output. Here is a simple example, # Shows only the process listing. $ ps -p 812 PID TTY TIME CMD 812 ? 00:00:00 rsyslogd # List both process and its threads $ ps -Lp 812 PID LWP TTY TIME CMD 812 812 ? 00:00:00 rsyslogd 812 814 ? 00:00:00 rsyslogd 812 815 ? 00:00:00 rsyslogd 812 26014 ? 00:00:00 rsyslogd The IDs 814, 815 and 26014 correspond to threads so you cannot use ps -p to list them. A better way to find whether a process is running is to use kill -0 as mentioned below, $ kill -0 813 bash: kill: (813) - No such process $ kill -0 814 bash: kill: (814) - Operation not permitted $ ps -p 814 PID TTY TIME CMD Also, the process IDs run from 1 to 32767 and roll over, so don't be surprised if you see gaps. The gaps just indicate that those processes have exited. -- 0 _______________________________________________ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
