000 S 1002 31587 31586 0 72 0 - 502 wait4 pts/0 00:00:00 bash000 R 1002 31612 31587 0 77 0 - 795 - pts/0 00:00:00 pshong:~ $As you can see most processes are run by the root and are not associated w with any terminal (TTY=?). Some of these are daemons, or servers. Another option -Hdisplays the process hierarchy, ie parent-child relationship. For example: [email protected]:~$ ps -efH | grep S900432DS900432D 32628 32625 0 21:19 ? 00:00:00 sshd: [email protected]/0 S900432D 32629 32628 0 21:19 pts/0 00:00:00 -bashS900432D 958 32629 0 22:20 pts/0 00:00:00 ps -efHS900432D 959 32629 0 22:20 pts/0 00:00:00 grep S900432D[email protected]:~$ The above command line consists of two commands ps -efHand grep S900432Dconnected by a pipe ("|"), which links the standard output of the first command with the standard input of the second command. The command greppicks up those input lines that contains the string "S900432D". The output in the above command line shows all processes started by the user "S900432D". It also reveals hierarchical structures of these processes. Try all commands used in this questions and try to understand the output with the helpof manual page of the pscommand. 7.Killing ProcessesYou can kill any process you own by sending the signal SIGKILL (signal 9). Firstly you need to find out the PID of the process you want to kill, then use the command kill -9 pidNote you cannot kill a process that is owned by other users. However root can kill anyprocess.