Terminating a job after a certain time, or after other criteria are met, usually involves having one process to run the job and another to monitor the completion criteria. In this tip you learn how to have a process manage the time while the real job runs. You also learn how to use the signal and trap facilities to terminate one of these tasks if the other finishes prematurely.
Traditionally, Unix/Linux/POSIX filenames can be almost any sequence of bytes, and their meaning is unassigned. The only real rules are that "/" is always the directory separator, and that filenames can't contain byte 0 (because this is the terminator). Although this is flexible, this creates many unnecessary problems. In particular, this lack of limitations makes it unnecessarily difficult to write correct programs (enabling many security flaws), makes it impossible to consistently and accurately display filenames, causes portability problems, and confuses users. more ....
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