This blog is written mainly to write and see how to use the Help command from the command
Here Under the first type command, as follows
type
: View command of command type
type cd
cd is a shell builtin
# type ls
ls is aliased to `ls --color=auto'
1. The internal command format command to get help:
Help the COMMAND
# help cd
2. External command format command to get help:
the COMMAND --help
# ls --help
3. Check the command command (manual) Manual format:
man the COMMAND
# man cd
Note manual manual is divided chapters; man # Command (# represents the chapter number)
（图中的数字与下方的数字对应，每个数字对应的内容）
1：所有用户可以使用的命令（/bin, /usr/bin, /usr/ local/bin）
2：系统内核调用，不是每个命令都有系统调用（如：man 2 read）
3：库调用
4：特殊文件（设备文件）如：/dev/tty1
5：文件格式（配置文件的语法）
6：游戏
7：杂项（Miscellaneous）
8:管理命令（/sbin, /usr/sbin, /usr/local/sbin）如：fdisk
<>：必须给出内容
[] ：可选内容
..：可以有多个
a|b|c：多选一
{}：分组（没有特殊意义）
Command Manual Small title probably means :
NAME: command name and function brief description
SYNOPSIS: instructions, including the options available
DESCRIPTION: detailed description of the command functions, possibly including the meaning of each option
OPTIONS: explain the significance of each option
FILES: this command configuration file
BUGS: report BUG who
eXAMPLES: example of use
SEE AISO: additional reference
Check the manual to use the command:
turned back one screen: SPACE
turned forward one screen: b
turn back one row: ENTER
turned forward one row: k
Find a manual method command:
/ KEYWORD (Keywords): Find back
n: Next
N: previous
? KEYWORD: look forward
n: Next
N: previous
q: quit
4. The online manual (there is a hyperlink stable document, info is the information page, provide more detailed information about the author, version, and when publishing, man manual tells you how to use):
info the COMMAND
#info ls
The vast majority of the program has a corresponding help files, stored in / usr / share / doc folder (almost commands to use and related manuals and documentation in this directory) as:
#ls /usr/share/doc/ntpdate-4.2.6p5/
COPYRIGHT
The above method did not use it, there's a method:
6. Baidu