从man(1)手册页：
\n\n\nRun Code Online (Sandbox Code Playgroud)\nSEARCH PATH FOR MANUAL PAGES\n man uses a sophisticated method of finding manual page files, based on\n the invocation options and environment variables, the /etc/man.config\n configuration file, and some built in conventions and heuristics.\n\n First of all, when the name argument to man contains a slash (/), man\n assumes it is a file specification itself, and there is no searching\n involved.\n\n But in the normal case where name doesn\xe2\x80\x99t contain a slash, man searches\n a variety of directories for a file that could be a manual page for the\n topic named.\n
不过里面还有很多文字。我会让你在闲暇时阅读它。
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