有时候，man ls 发现没有帮助文档，可以快递打开浏览器检索 "man ls" 。

# yum list | grep man | grep pages

gl-manpages.noarch                       1.1-7.20130122.el7            @base
libguestfs-man-pages-ja.noarch           1:1.40.2-10.el7               base
libguestfs-man-pages-uk.noarch           1:1.40.2-10.el7               base
man-pages.noarch                         3.53-5.el7                    base
man-pages-cs.noarch                      0.18.20090209-17.el7          base
man-pages-de.noarch                      1.8-4.g7c4902d.el7            epel
man-pages-es.noarch                      1.55-21.el7                   base
man-pages-es-extra.noarch                1.55-21.el7                   base
man-pages-fr.noarch                      3.52-3.el7                    base
man-pages-it.noarch                      3.15-2.el7                    base
man-pages-ja.noarch                      20130615-6.el7                base
man-pages-ko.noarch                      2:20050219-25.el7             base
man-pages-overrides.x86_64               7.9.0-1.el7                   base
man-pages-pl.noarch                      1:0.3-4.el7                   base
man-pages-ru.noarch                      3.41-3.20120901.el7           base
man-pages-zh-CN.noarch                   1.5.2-4.el7                   base

# man man 
...
       The table below shows the section numbers of the manual followed by the types of pages they contain.

       1   Executable programs or shell commands
       2   System calls (functions provided by the kernel)
       3   Library calls (functions within program libraries)
       4   Special files (usually found in /dev)
       5   File formats and conventions eg /etc/passwd
       6   Games
       7   Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7)
       8   System administration commands (usually only for root)
       9   Kernel routines [Non standard]
...

所以，man man 等于 man 1 man。

# rpm -qa | while read line ; do rpm -ql $line | grep -q man[1-9] && echo $line  ; done

打印所有包含man文档的软件包，实际比想象的要包很多。