man命令详解

 - 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, e.g. /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]