當我在centos8裏執行man X操作時輸出如下：
[root@promote ~]# man X
No manual entry for X
原因是沒有安裝xorg-x11-docs包。
執行如下命令：
[root@promote ~]# dnf install xorg-x11-docs
現在man X作用正常了：
[root@promote ~]# man X
X(7) Miscellaneous Information Manual X(7)
NAME
X - a portable, network-transparent window system
OVERVIEW
The X Window System is a network transparent window system which runs on a wide range of computing and graphics machines. It should be relatively straightforward to build the
X.Org Foundation software distribution on most ANSI C and POSIX compliant systems. Commercial implementations are also available for a wide range of platforms.
The X.Org Foundation requests that the following names be used when referring to this software:
X
X Window System
X Version 11
X Window System, Version 11
X11
X Window System is a trademark of The Open Group.
DESCRIPTION
X Window System servers run on computers with bitmap displays. The server distributes user input to and accepts output requests from various client programs through a variety
of different interprocess communication channels. Although the most common case is for the client programs to be running on the same machine as the server, clients can be run
transparently from other machines (including machines with different architectures and operating systems) as well.