最近在读APUE,有一段话不是很理解

Question

第13章关于守护进程的编写规则:

1. Call fork and have the parent exit. This does several things. First, if the daemon was started as a simple shell command, having the parent terminate makes the shell think that the command is done.

不是很理解,希望理解的帮一下~

Answer 1

就是你在虚拟终端或者SSH里执行一个普通命令，比如vim。那个命令会一直运行着，你就看不到shell的提示符。守护进程应该是在后台运行的。所以fork一个子进程，再结束自身，shell就以为你的程序结束了，会显示提示符，也就是程序和shell（和终端）脱离了关系。