The kill CommandWhen you use the kill command with a process, you stop whatever that process is doing. One hazard with commands of this nature is that if you are using a program like the vi editor and you kill it, you may lose your work as a result. Although the kill command is mainly used to end a process, it can also be used to send signals to a process. Signals can be sent to indicate an action. There are actually many signals that you can use with the kill command. If you use the kill command with the l option, you can see a list of everything that Unix can signal with: >kill -l 1) SIGHUP 2) SIGINT 3) SIGQUIT 4) SIGILL 5) SIGTRAP 6) SIGIOT 7) SIGBUS 8) SIGFPE 9) SIGKILL 10) SIGUSR1 11) SIGSEGV 12) SIGUSR2 13) SIGPIPE 14) SIGALRM 15) SIGTERM 17) SIGCHLD 18) SIGCONT 19) SIGSTOP 20) SIGTSTP 21) SIGTTIN 22) SIGTTOU 23) SIGURG 24) SIGXCPU 25) SIGXFSZ 26) SIGVTALRM 27) SIGPROF 28) SIGWINCH 29) SIGIO 30) SIGPWR Documentation for the software you run on your system often includes information on the signals to which it will respond. The most important signals you'll use are SIGHUP and SIGKILL. The SIGHUP signal will hang up and reload the server's process configuration information. SIGKILL should be pretty self-explanatory; KILL in all capital letters should help you remember that this is the signal to kill processes. To use the kill command, enter kill -<signal number> <process ID> <process ID> .... For example, to kill process number 8832, type the following: >kill -9 8832 If you look at the process listing again, PID 8832 will be gone. You've successfully killed it! Check by verifying with the ps command and make sure that the process has ended. You can also check with the jobs command as well.
So now that you are comfortable working with commands such as top, jobs, ps, and kill, let's look at some of the other commands you will need to know to control processes within Unix, namely cron and at. |