Introduction to Linux

What is Linux?

a Unix-like computer operating system but free and open-source.

The Linux Operating System (OS) is a large program (mostly coded in C) that turns the computer into a useable machine.

Account

Each user has their own space, called their account.

ad type your ID and RETURN

Password: type your password and

RETURN. It does not appear.

$ The Linux prompt提示 (or similar). You can now enter commands.

Access denied Password: Login ID and password not match

logout

^D ：同时按CONTROL和D键

exit

The Shell

The Linux user interface is called the shell

ssh student@127.0.0.1 2000：远程联机

rz：上传文件

sz x：下载文件

Typing Commands

date:Gives time and date

cal 3 1997:Calendar

who

pwd 当前路径

ifconfig

man cal: Manual pages

uptime

Machine’ s ‘ up ’ time

显示系统已经运行了多长时间、当前登入用户数量、过去1分钟、5分钟、15分钟内的负载信息。

hostname

Name of the machine

apropos topic（要查的命令的topic）

如果你不知道完成某个特定任务所需要命令的名称，可以使用一个关键字通过Linux apropos实用程序来搜索它。该实用程序可以搜索关键字并且显示所有包含匹配项的man页面的简短描述

Lists commands related to topic

和 man -k一个功能

man -k topic（要查的命令的topic）

whatis cmd： One-line description（描述一个命令）

which cmd: 定位一个命令

locate cmd ：List files with cmd in their name (or path)

locate your_file_name 即可查找指定文件

Output of these commands can be very long. See one screenful at a time with:

locate game | more

apropos print | more

Press enter/spacebar to go on; ^C/q to stop

Control Characters

Changing your Password

passwd:

System Directories 文件操作

home directory, which is named after your login ID.

pwd showing current directory

root Account

root: super user, who has the full rights to all resources

home directory: /root
changing to root account: $sudo -i
add a new user account: #adduser account-name

终端切换

Windows: ALT+F1, ALT+F2

Pathnames

路径名是目录名的序列(以/ 分隔)，用于标识目录的位置

Absolute Pathnames

树的顶部(根)和感兴趣的目录之间的目录名称序列。

/bin

/etc/terminfo

/home/ad

/home/student/proj1

Relative Pathnames

从当前所在目录到感兴趣目录的目录名称的顺序。

proj1 if you are in student

student/proj1 if you are in home

Working with Directories

Moving between Directories

student到proj1中

cd proj1：（current working directory.）

pwd ：Print name of current working directory

Move back to directory student (the parent directory):cd … (返回上一级目录)

proj1到proj2

…是上一级目录

…/proj2 is a relative pathname

Investigate the System

cat file 命令用于连接文件并打印到标准输出设备上

List file

ls Directory listing

ls List current dir.

ls /etc List /etc

ls -F -F option shows types

Making / Deleting / Renaming Directories

Creating a Text File

cat > file

这将把你在键盘上输入的文本输入到文件中，直到你输入^D (CONTROL和D一起)

Listing Files

cat file List the file

more file List the file a screen at a time. Type spacebar to go on; ^C to stop

less file Like more but more powerful

head file List the first few lines

tail file List the last few lines

Other Basic Commands

I/O Redirection

Most commands output to the screenls

Output can be redirected to a file with‘>‘:

ls > dir.txt

cal 1997 > year1997

">"把输出输入到文件中

“>>”:cal 1998 >> years把输出加到文件后

Concatenate two files:

cat f1 f2 > fs
Input redirection (less common) uses ‘<‘

wc < years
Combine input and output redirection:

wc < years > year-counts

Editor

vi is a text editor.

vi shows you part of your file and allows you to enter commands that change something

命令模式:移动光标，移动到文件的不同部分，发出编辑命令，切换到插入模式。
插入模式:无论你输入什么都将被放入文件中(不解释为命令)。

光标移动命令in command mode

Scrolling Commands

delete stuff

Changing Text

Insert Mode

要退出插入模式(回到命令模式)，按下“Esc”(escape键)。

有一个状态行(屏幕底部)，告诉你你在什么模式/命令

Copy & Paste

p paste text last copied to the right of the cursor

yy copy current line

ye copy from the cursor to the end of the word

Searching and Replacing

/textsearch forward for text

?textsearch backward for text

Saving and Exiting

Other commands

chmod