8.2. What's /etc/update? What does it do?
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This article is from the 3b1 computers FAQ, by John B. Bunch with numerous contributions by others.
8.2. What's /etc/update? What does it do?
/etc/update is an antiquated command which is no longer necessary to be used. It is not a shell script, but could easily be one. The executable basically takes one argument, the number of seconds to sleep, or defaults to 30 (I believe). It then sleeps that interval and then issues a sync(2) system call. This is a continuous process -- it detaches itself from the current tty with the setpgrp(2) call, and closes all file descriptors 0, 1, and 2 (stdin, stdout, and stderr). It was to be run by /etc/init, as a boot-time process, and was to remain there for the duration of the machine's uptime.
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