一 help
内部命令，Shell提供，寻求帮助可以用help，如help echo
外部命令，Shell不提供，Shell调用，XX –help，如ls –help
二 man
man XX
[root@wentasy root]# man 7 man The manual divs are traditionally defined as follows: 1 Commands Those commands that can be executed by the user from within a shell. 2 System calls Those functions which must be performed by the kernel. 3 Library calls Most of the libc functions, such as qsort(3)) 4 Special files Files found in /dev) 5 File formats and conventions The format for /etc/passwd and other human-readable files. 6 Games 7 Macro packages and conventions A description of the standard file system layout, net- work protocols, ASCII and other character codes, this man page, and other things. 8 System management commands Commands like mount(8), many of which only root can execute. 9 Kernel routines This is an obsolete manual div. Once it was thought a good idea to document the Linux kernel here, but in fact very little has been documented, and the documentation that exists is outdated already. There are better sources of information for kernel develop- ers.
三 info
info ls：和man page类似，比man page多一个功能，可以链接，带*号的，按回车链接可以过去，Shfit+u返回
四 ReadMe文件
软件全套的RedeMe文件：ls /usr/share/doc/XXX
[root@wentasy root]# ls /usr/share/doc/Display all 729 possibilities? (y or n)
五 howto文档
http://tldp.org/HOWTO/HOWTO-INDEX/howtos.html
http://man.chinaunix.net/linux/how/HOWTO-INDEX-3.html
tldp.org
http://tldp.org/
六 Google
Google：适合英文关键字，推荐使用，多翻几页可以翻到英文的帮助文档
七 百度
Baidu：适合中文关键字
记住这句话：
菜鸟总是问别人，高手总是快速的寻求帮助。
附几个快捷键
Ctrl + C：停止进程
Ctrl + Z：暂停
Ctrl + L：清屏
Ctrl + S：不管输入什么没反应，直到输入Ctrl+Q退出此状态
Ctrl + R：追踪命令历史，搜索历史
/-X：快速搜索，n顺序往下查找，shift+N往上查找
@Wentasy总有一天，我会丢下我所有的疲倦和理想，
