Which command is used to terminate all processes in your own system except the login shell? A. kill 1 B. kill 0 C. cancel all D. cancel 1 E. None of the above

The correct answer is: A. kill 1

The kill command sends a signal to a process. The signal can be used to terminate the process, or to do other things, such as suspend or stop the process. The signal number is specified after the kill command.

The signal number 1 is the SIGHUP signal. This signal causes the process to terminate. However, the login shell is a special process that is not terminated by the SIGHUP signal.

The other options are incorrect.

• Option B, kill 0, sends the SIGTERM signal to the process. This signal is also used to terminate the process, but it is not as reliable as the SIGHUP signal.
• Option C, cancel all, is not a valid command.
• Option D, cancel 1, is a valid command, but it sends the SIGINT signal to the process, which does not cause the process to terminate.
• Option E, None of the above, is incorrect because option A is the correct answer.