基础命令: man

*

man 命令可以对其他命令进行解释和功能性阐述

display online manual documentation pages

❯ man man
......
MAN(1)                                                                          General Commands Manual                                                                         MAN(1)

NAME
     man, apropos, whatis – display online manual documentation pages

SYNOPSIS
     man [-adho] [-t | -w] [-M manpath] [-P pager] [-S mansect] [-m arch[:machine]] [-p [eprtv]] [mansect] page ..
     man -f [-d] [-M manpath] [-P pager] [-S mansect] keyword ...
     whatis [-d] [-s mansect] keyword ...

     man -k [-d] [-M manpath] [-P pager] [-S mansect] keyword ...
     apropos [-d] [-s mansect] keyword ...

DESCRIPTION
     The man utility finds and displays online manual documentation pages.  If mansect is provided, man restricts the search to the specific section of the manual.
     The sections of the manual are:
           1.   General Commands Manual
           2.   System Calls Manual
           3.   Library Functions Manual
           4.   Kernel Interfaces Manual
           5.   File Formats Manual
           6.   Games Manual
           7.   Miscellaneous Information Manual
           8.   System Manager's Manual
           9.   Kernel Developer's Manual

     Options that man understands:
     -M manpath
             Forces a specific colon separated manual path instead of the default search path.  See manpath(1).  Overrides the MANPATH environment variable.
     -P pager
             Use specified pager.  Defaults to “less -sR” if color support is enabled, or “less -s”.  Overrides the MANPAGER environment variable, which in turn overrides the PAGER
             environment variable.
     -S mansect
             Restricts manual sections searched to the specified colon delimited list.  Defaults to “1:8:2:3:3lua:n:4:5:6:7:9:l”.  Overrides the MANSECT environment variable.
     -a      Display all manual pages instead of just the first found for each page argument.
     -d      Print extra debugging information.  Repeat for increased verbosity.  Does not display the manual page.
     -f ......
     .
     .
     .

• man页面一般可以分为8种命令类型

The sections of the manual are:
           1.   General Commands Manual
           #		用户命令
           2.   System Calls Manual
					 #		系统调用           
           3.   Library Functions Manual
           #    C 库函数
           4.   Kernel Interfaces Manual
           #		设备与网络（内核）接口
           5.   File Formats Manual
           #		文件格式
           6.   Games Manual
           #		游戏与屏保
           7.   Miscellaneous Information Manual
           #		环境、表、宏
           8.   System Manager's Manual
           #		系统管理员命令和后台运行命令
           9.   Kernel Developer's Manual
           #		内核开发者手册

• man命令的允许输入选项