Unit 1.2 Beginning to Unix systems
Presenter Notes
Unit objectives
- After completing this unit, you should be able to:
- Log in and out of the system
- State the structure of Unix commands
- Execute basic Unix commands
- Find help
Presenter Notes
在该单元学习结束时,需要会 -登录登出系统 -清楚Unix命令结构 -执行简单的Unix命令 -能够找到帮助
Unix is multiuser and multitasking
- Unix is a multiuser, multitasking operating system.
- Multiple users can run multiple tasks simultaneously, independent of each other.
- You always need to log in before using the system.
- Identify yourself with user name and password.
- “root” is the superuser of the system.
- There are multiple ways to log in to the system.
- You can log in through the console: Directly attached keyboard, mouse, monitor.
- Usually used for virtual terminals
- You can log in through a network connection (for example, SSH or Telnet).
Presenter Notes
UNIX是多用户和多任务的操作系统
- 通常,必须要登录操作系统才能使用
- 登录Unit/Linux可以有多种方式
- 通过Console输入登录,例如:鼠标、键盘等外设
- 通过虚拟终端登录
- 网络连接登录,使用SSH或者Telnet登录
login and command prompt
Login with your username and password.
Login:
Password: < NO ECHO !!!>
$The command prompt indicates that the system is ready to accept commands.
- The dollar sign ($) usually means you are logged in as a regular user.
- The hash sign (#) usually means you are logged in as root.
To logout: exit / ctrl-d / logout
Presenter Notes
操作练习login与logout。Hint:与Windows不同,密码位数都被隐藏
Command syntax
Unix commands have the following format:
$ command options arguments
ls
ls /home
ls -l
ls -l /homeMultiple options
ls -a -l -h /home
ls -alh /home
Presenter Notes
常用命令ls窥见Unix命令的语法,用help查看指令的syntax 错误例子:
- mail - f personal
- who-u
- mail test root -s
- -u who
- who -m-u
- who -m u
Basic commands
- passwd: change your password.
- date: show the current date and time.
- cal: show the calender.
- su / sudo : switch user (usu. root)
- who: find out who is active on the system.
- whoami / who am i : find out who you are.
- write : write a message to a logged in user.
- wall : broadcast a message to all logged in users.
- mail : send/receive mail.
- clear: clear the screen.
- echo: write a message on the screen.
Presenter Notes
- ls:列出当前目录下文件
- cd:切换目录
- find:通配符找文件
- talk:与其他在该系统登录的用户对话
- 常用快捷键
Help : man command
- Man is most powerful!
- With the man command, you can read the manual page of commands.
- The manual page consists of:
– Name: The name of the command and a one-line description
– Synopsis: The syntax of the command
– Description: Explanation of how the command works and what it does
– Options: The options used by the command
– Files: The files used by the command
– Bugs: Known bugs and errors
– See also: Other commands related to this one
Presenter Notes
帮助命令:man 格式:man 【命令】 作用:获取指定命令的帮助 例如查看ls的帮助命令 格式:man ls
man sections
The collection of manual pages is divided into nine sections:
- Executable or shell commands
- System calls
- Library calls
- Special files (usually found in /dev)
- File formats and conventions
- Games
- Miscellaneous (macro packages and so on)
- System administration commands
- Kernel routines (non-standard)
Presenter Notes
查看命令拥有哪个级别的帮助 格式:man -f 【命令】 相当于 whatis 【命令】 man的级别: 1 : 查看命令的帮助 2 : 查看可被内核调用的函数的帮助 3 : 查看函数和函数库的帮助 4 : 查看文件的帮助(主要是/dev目录下的文件) 5 : 查看配置文件的帮助 6 : 查看游戏的帮助 7 : 查看其它杂项的帮助 8 : 查看系统管理员可用命令的帮助 9 : 查看和内核相关文件的帮助
Certain subjects appear in multiple sections.
To select correct section, add section number:
– man 1 passwd (about the passwd command)
– man 5 passwd (about the passwd file)The -k option of the man command or the apropos command prints out a description of all entries that match the given keyword.
Presenter Notes
- $man -k print
- arch (1) 打印机器的架构
- date (1) 打印或者设置系统时间
- logname (1) 打印登录用户名
Other help
- info
- the --help option
- the Internet
Presenter Notes
info指令是man 指令的详细内容。但man 使用起来要方便的多。一个man 只有一页,而info总是将它们的内容组织成多个区段(节点),每个区段也可能包含子区段(子节点)。info工具可显示更完整的最新的GNU工具信息。通常man中若包含的信息概要在info中也有时,会有提示:“请参考info页更详细内容”。
Unit summary
- Log in and out of the system
- State the structure of Unix commands
- Execute basic Unix commands
- Find help
References
- Unit 3. Using the system, Linux Basic and Installation , ERC 7.2, IBM
- Unit 6. Linux documentation, Linux Basic and Installation , ERC 7.2, IBM