Linux中的man命令

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]
在shell中输入 man 数字 命令/函数 即可以查到相关的命令和函数。如果不加数字，那man命令默认从数字较小的手册中寻找相关命令和函数。