Help on getting commands on a Linux system and how the chapters of the man document are divided

1. Order--Help

2. Man command

The latter more detailed

First help the middle angle brackets <> and square brackets [] as well as the ellipsis ... The meaning,

The expression within square brackets (the character between "[" and "]") is optional (the parentheses are removed when the command is written).
The expression within the angle brackets (the character between "[" and "]") is an expression that must be replaced (and the parentheses are removed).

An ellipsis indicates that the option can be single or multiple

Section and description of man document chapters

Name: Names and basic functions

Synopsis: Brief Help

[]: Optional content

<>: Required Content

A|b: Two Choose one

... : The same content can appear multiple times

DESCRIPTION: Detailed Function description

EXAMPLES: Using the example

AUTHOR: Author

REPORTING BUGS: report Bug Location

Copyright: Copyrights

See ALSO: Reference method

Help on getting commands on Linux systems and how chapters for man documents are divided