Linux summary and linux learning Summary

Linux summary and linux learning Summary

I. file commands:

Go to the home/liuyazhuang directory

Cd/home/liuyazhuang

 

Ls:

Ls

Mkdir:

MkdirfamilyA

Switch the cd directory to the familyA directory:

CdfamilyA

 

Ls displays the content of the current directory:

Ls

 

Touch creates an empty file

Touchfather.txt has A father in family.

Touchmother.txt has a mother.

Touchson.txt son

Touchdaughter.txt daughter

 

Create a directory using mkdir

Mkdirhouse

 

Cd switch directory

Cdhouse

 

Mkdir create directory

Mkdirkitchen kitchen

Mkdirbathroom toilet

MkdirroomA

MkdirroomB

MkdirroomC

Touchsofa.txt sofa

 

Ls:

Ls display

 

Cd switch directory

CdroomB

 

Touch creates an empty file

Touchbed.txt

Echo "Your are the best boy."> book.txt creates a file with simple content

Catbook.txt View File Content

 

Cd switch directory

Cd .. back to the upper-level directory

CdroomC

 

Touch creates an empty file

Touchbed.txt

Echo "Your are the best girl."> book.txt

Catbook.txt

Touchdoll.txt

 

Cp

Cpdoll.txt/home/liuyazhuang/familyA/house/roomB

 

Cd switch directory

Cd ..

CdroomB

 

Ls:

Ls display

 

Cd switch directory

Cd ..

 

Mv mobile File

Mvsofa.txt/home/liuyazhuang/familyA/house/roomB

 

Cd switch directory

CdroomB

 

Ls:

Ls display

 

Rm delete file directory

Rmdoll.txt

More less page display

Morebook.txt

 

Wc displays the number of document lines, characters, and characters

Wcbook.txt

 

Find to find the specified file

Find-name book.txt

 

Grep searches for a specified string

Grepbest book.txt

 

Pwd displays the current directory

Tree display directory tree

Rmdir Delete empty directory

Rmdirbathroom

 

Establish a soft connection with ln-s

Ln-s/home/liuyazhuang/familyA/house/roomB/home/roomB

 

Ii. system management commands

Stat displays information about the specified file.

Cd/home/liuyazhuang

StatfamilyA

 

Who and w show online login users

Who

 

Whoami displays the user's identity

 

Hostname display Host Name

Hostname

Hostname-I display Host IP Address

 

Uname: displays system information

Uname-a displays all information (kernel name, host name, kernel version number, kernel version, hardware name, processor type, hardware platform type, and operating system name)

 

Top displays the dynamic display process of processes that consume the most resources in the current system, real-time monitoring

Ps displays Transient Process status

Ps-aux displays the status of all transient processes

 

Du displays the total disk space used by the specified file (directory). You can use -- help to view help.

Du

DufamilyA

Du-h familyA

 

Df displays the disk space usage of the file system

Df

Df-h

 

Free displays the usage of the current memory and swap space

 

Ifconfig displays network interface information

 

Ping to test network connectivity

 

Netstat displays network status information

 

Iii. Backup and compression commands

Gzip command

Compress all files in the familyadirectory under the/home/liuyazhuangdirectory into A. GZ file.

Cd/home/liuyazhuang

Tar-cvf/home/liuyazhuang/familyA.tar/home/liuyazhuang/familyA is first packaged, because gzip cannot directly compress the Directory

GzipfamilyA.tar Compression

Gzip-l familyA.tar.gz

 

Decompress familya.tar

Gzip-dv familyA.tar.gz

Gzip-v-9 familyA.tar high compression ratio

Gzip-l familyA.tar.gz

 

Gzip-dv familyA.tar.gz

Gizp-v-1 familyA.tar low compression ratio

Gzip-l familyA.tar.gz

 

Bzip2 command

 

Compress all the files in the familyadirectory under the/home/liuyazhuangdirectory into the. bz2 file.

Cd/home/liuyazhuang

Tar-cvf/home/liuyazhuang/familyA.tar/home/liuyazhuang/familyA

Bzip2-z familyA.tar compression requires parameter-z

 

Decompress liuyazhuang.tar.bz2

Bzip2-d familyA.tar.bz2

 

Tar command

Pack all the files in the/home/liuyazhuang/familyA Directory into/home/liuyazhuang/familyA.tar

 

Pack only, not compress

Tar-cvf/home/liuyazhuang/familyA.tar/home/liuyazhuang/familyA

 

After packaging, compress with gzip

Tar-zcvf/home/liuyazhuang/familyA.tar.gz/home/liuyazhuang/familyA

 

Compress With bzip2 After packaging

Tar-jcvf/home/liuyazhuang/familyA.tar.bz2/home/liuyazhuang/familyA

 

For special example, the file name behind "f" is retrieved, and we use" .tar "for identification on our website.

If zzip is added, .tar.gz or. tgz is used to represent the compressed tar file in gzip.

If July 2 is added, .tar.bz2 is used as the document name.

 

Iv. VIM Editor

VIM Editor

 

Create a bank.txt file in the/home/liuyazhuang/directory.

Cd/home/liuyazhuang/familyA/

Touchbank.txt

Vimbank.txt

Data command I enters the insert mode

Input content

ICBC

RMB: 10000000000

USD: 100000000000

User: familyA. father

 

Ctrl + C Exit the insert mode or Press ESC to switch to the command mode

 

: Wq press enter to save

 

Edit bank.txt without saving and exit

Vimbank.txt

Data command I enters the insert mode

Enter whatever content

Ctrl + C Exit the insert mode or Press ESC

: Q! Press enter to force exit

 

Edit bank.txt and display the row number

Vimbank.txt

: Setnumber press ENTER

: Q: Press enter to exit normally.

 

5. users and groups

Add an account

 

Useradd-m ltw parameter-m is used to set the system to automatically create the user root directory when adding an account

Adduser

 

Modify the logon name of an ltw account

Usermod-l litingwei ltw

 

Modify the logon directory of the litingwei account (Note: You must manually create the litingwei directory before modification)

Usermod-d/home/litingwei

 

Lock user litingwei account password

The account is unavailable after usermod-L litingwei is locked.

 

Unlock user litingwei account and password

Usermod-U litingwei

 

Add a group

Groupaddsuperman

 

Modify a superman Group

Groupmod-g 355 superman

 

Delete a superman Group

Groupdelsuperman

 

Modify the root password (the root password has not been set. You can use it only after setting the password)

Passwdroot

 

Root, litingwei account Switch

Su-root

Or sudo-I to switch to root

 

Delete the litingwei account

Userdel-r litingwei (-r is deleted together with the user directory)

 

Vi. File Permissions

Show the file/home/liuyazhuang/familyA/bank.txt Permissions

Cd/home/liuyazhuang/familyA/

Ls-l

 

Switch to litingwei user

Sulitingwei

 

Use litingweiaccount accounts to read and write bank.txt

Catbank.txt

Vimbank.txt at this time, litingwei does not have the permission to modify the file

 

Switch back to liuyazhuang

Suliuyazhuang

 

Modify bank.txt to allow other users to read and write

Chmodo + w bank.txt

 

Switch back to litingwei

Sulitingwei

 

Modify bank.txt

Vimbank.txt

 

7. Build a java environment

Step 1 install jdk

Switch su-root to root user

Sudo-I directly switches to root without a password

 

1. Enter the usr directory

Cd/usr

 

2. Create a java installation directory under the usr directory

Mkdir java

 

3. Copy jdk-6u24-linux-i586.bin to the java directory

Cp/home/liuyazhuang/Desktop/jdk-6u24-linux-i586.bin/usr/java/

 

4. Install jdk

Cd/usr/java

 

/Jdk-6u24-linux-i586.bin

5. After the installation is complete, create a link for him to save the directory Length

Ln-s/usr/java/jdk1.6.0 _ 24 // usr/jdk

 

6. Edit the configuration file

Vim/etc/profile

Add the following content:

JAVA_HOME =/usr/jdk

CLASSPATH = $ JAVA_HOME/lib/

PATH = $ PATH: $ JAVA_HOME/bin

Export PATH JAVA_HOME CLASSPATH

 

8. Restart the machine or source/etc/profile

 

Sudo shutdown-r now

 

9. view the installation status

Java-version

Java version "1.6.0 _ 24"

Java (TM) SE Runtime Environment (build1.6.0 _ 24-b07)

Java HotSpot (TM) Client VM (build 19.1-b02, mixed mode, sharing)

 

Step 2 install tomcat

Tar-zxvf apache-tomcat-6.0.29.tar.gz-C/opt (unzip to/opt)

Ln-s/opt/apache-tomcat-6.0.29 // opt/tomcat (create a link file)

Start tomcat

Cd/opt/tomcat/bin/

./Startup. sh (Note: points represent the current directory)

If it cannot be started, try

-I switch to the root user and restart

./Startup. sh

Test http: // 127.0.0.1: 8080/

 

Step 3 install eclipse

Tar-zxvf eclipse-SDK-4.2-linux-gtk.tar.gz-C/opt (decompress to the/usr/local directory and generate the/usr/local/eclipse directory)

Cd/opt/eclipse/

./Eclipse (Note: The point indicates the current directory)

 

8. ssh remote Logon

1. install openssh-server

Sudo dpkg-I openssh-client_1 % 3a5. 5p1-4ubuntu6_i386.deb

Sudo dpkg-I openssh-server_1 % 3a5. 5p1-4ubuntu6_i386.deb

If the network connection is connected, you can install sudoapt-get install openssh-server.

 

2. Set the ip address

Sudo ifconfig eth0 192.168.1.222 netmask 255.255.255.0

3. Start ssh-server.

$/Etc/init. d/ssh restart

Service ssh restart

 

4. confirm that the ssh-server is working properly.

$ Netstat-tlp

Tcp6 0 0 *: ssh *: * LISTEN-

The above output indicates that the ssh-server is already running.

 

5. log on to the server through ssh on the client. Assume that the IP address of the server is 192.168.0.103, And the logon username is hyx.

$ Ssh-l hyx 192.168.0.103

Next, you will be prompted to enter the password, and then you will be able to successfully log on to the server.

 

9. SSH Trust

1. Generate a key file on the first host (the hidden directory of. ssh is generated under the user root directory, and two files are generated under some Directories)

Id_dsa ------------ Private Key File

Id_dsa.pub ------------ Public Key File

Command:

Ssh-keygen-d

 

2. Copy id_dsa.pub with the file name authorized_keys2.

Change the authorized_keys2 attribute to 600, that is, the file owner has the read and write permissions, and the group users and other users are prohibited from reading and writing.

Command:

Cp id_dsa.pub authorized_keys2

Chmod 600 authorized_keys2.

 

3. Generate a key file on the second host

See the previous two steps

 

4. Copy the id_dsa.pub public key file under the/home/work/. ssh directory on server_1

Under the/home/work/. ssh directory of server_2 (Note: Do not overwrite id_dsa.pub of server_2, and change the name when copying it)

Command:

Scp id_dsa.pubwork @ server_2:. ssh/server_1.pub

 

5. view the. ssh directory files on server_2:

Authorized_keys2

Id_dsa

Id_dsa.pub

Server_1.pub

 

6. Put server_1.pub content in authorized_keys2. Be sure to use the append operation ">" "> ")

Command:

Cat server_1.pub> authorized_keys2

 

5. Test

Ssh work @ server_2

 

Level 1 (password-based security verification ),

You can log on to the remote host as long as you know your account and password,

All transmitted data is encrypted.

However, this authentication method cannot ensure that the server you are connecting to is the server you want to connect.

Other servers may pretend to be real servers, that is, being attacked by man-in-the-middle (mitm) attacks.

 

Level 2 (key-based security verification) relies on keys,

That is, you must create a pair of keys for yourself and put the public keys on the server to be accessed.

If you want to connect to the SSH server, the client software will send a request to the server, requesting your key for security verification.

After receiving the request, the server first searches for your public key in the user root directory of the server,

Then compare it with the public key you sent. If the two keys are the same, the server uses the public key to encrypt the challenge and send it to the client software.

After receiving the question, the client software can use your private key to decrypt it and then send it to the server.

 

Compared with the first level, the second level does not need to transmit user passwords over the network.

In addition, the second level not only encrypts all transmitted data, but also the "intermediary" attack method is impossible (because it does not have your private key ). However, the entire logon process may be slower.

LINUX learning experiences

First, tell you not to be afraid. You can install it as prompted. Then, read the following:

Linux installation in Windows

HQY published on 18:25:00
If you want to use both Windows and Linux systems on the same computer, you must first learn to install Linux on a computer with Windows systems installed.

For Windows/Linux systems with multiple operating systems, the installation sequence is to install Windows first, and then Linux. Next we will introduce how to install RedHat Linux 9.0 on a single hard disk that has been installed on Windows.

Preparations before Linux Installation
1. Collect hardware information in Windows
Before installing Linux, you need to use the Windows system to learn basic information about computer hardware, such as the memory size, sound card, display, mouse, and graphics card model.

2. Set the boot system from the CD
Linux supports several installation methods, but it is most convenient and fast to directly start the installation with a CD boot. If you want the machine to start with a CD, you need to modify the BIOS settings, change the CD-ROM to the first place on the machine order.

3. Linux partition
Linux partition Representation
Partitioning separates disk drives into independent areas. Each area is like a separate disk drive. in DOS/Windows, disk partitions can be divided into C, D, and E disks. However, in Linux, disks are managed and used as block device files, which start with/dev (device abbreviation.

For example, in Linux, "/dev/hda1" is used to represent the C drive in Windows.
Among them, hd indicates the IDE Hard Disk (sd for SCSI hard disk); hda indicates the first IDE Hard Disk (hdb for the second);/dev/hda1 indicates the primary partition, and the logical partition starts from 5, for example: /dev/hda5,/dev/hda6,/dev/hda7, etc.

Prepare partitions for Linux
Linux partitions are different from Windows partitions and cannot be shared. Therefore, you need to create an idle partition for Linux, preferably the last partition. 1. Use the Partition Magic (Partition Magic) software in Windows to free up space on disk D to create a new Partition edisk (or use an existing idle edisk). The file type is currently set to FAT32, for Linux partition creation later, RedHat 9.0 requires about 4 ~ 5 GB space.

4. Linux File System
File systems vary with operating systems. The Windows File System is FAT16, FAT32, and NTFS. Linux file systems can be divided into ext2, ext3, swap, and vfat. Ext2 supports a file name of up to 255 characters. ext3 is based on ext2. It mainly reduces the time it takes to restore the file system after the system crashes. RedHat 9.0 defaults to ext3; swap zone swap is used to support virtual memory; Windows FAT partition is displayed as vfat file type in Linux.

1. boot with the first installation disc of RedHat 9.0. The installation menu will appear after the system is started.

The installation Menu provides a graphical and text Installation Method for the user to choose from. Press enter to select the graphical mode for installation. Before entering the installation mode of the graphic screen, RedHat 9.0 is more than the previous version, that is, it prompts to check the installation disc media, or you can press the "Skip" button to Skip the detection.

2. Then the installer automatically detects the hardware, including the video card (Display Card), display, and mouse configuration, and then enters the Installation Wizard of the graphic screen. In the "language selection" screen, select "simplified Chinese", so that the text on the subsequent installation interface will be changed to Chinese. On the keyboard configuration screen, use the default American English keyboard. Select... the remaining full text>

Who has learned from Linux?

I am studying linux every day and have some experiences to share with you.

First of all, it is useless to learn about linux simply by reading books. Because the linux kernel and software are updated too quickly, the software configuration method described in the book is often not suitable (mostly version conflicts or incompatible ), the hardware and software configurations of your machine are different from those of the machine used in the book, which may also cause software installation failure. In comparison, many articles on the Internet are quite new, and they are much better than books in solving practical problems. However, the book has the advantages of the book, the book is very comprehensive, the configuration of a command or software has been analyzed a lot, and most articles on the Internet are targeted. Therefore, it is necessary to combine the book with the network and learn the principles through the book. If the actual problem cannot be solved, Baidu or google more.

In addition, although everyone prefers the beautiful mm, when learning linux, they still need to contact the "man": when P encounters a problem, in addition to online queries, we need to use the man command in linux to find help.

The last thing to say is that although apt-get or yum (depressing) is very convenient, it is best to download the source code package to install the software, I can't install apt-get, because now I want to learn more complex things in linux, so I will take a shortcut when I need to use it in the future. In addition, try multiple parameters as much as possible during configure and set your own -- prefix path. Also, do not worry about installing software to mess up the system. If the system crashes, reload the system once. If you install the system several times, you will get started with linux. (I installed the system four or five times a day.) try multiple linux versions as much as possible when installing the system. There are many releases of linux. They are different in many places, so I don't know what else I used. For example, I used to use red hat to start the inittab settings. When I used ubuntu, I found that inittab was gone, instead, events/is replaced, and the startup level is not rh. 3 is the Terminal 5 is the graph, and the ubuntu 2-5 is the same, there are many differences (I will briefly introduce the differences between rh AND ubuntu IN THE NEXT blog ).

In short, I think it is more convenient to use windows for entertainment, but if you want to use a computer to work (programming, server, etc.), you should use linux. To learn linux well, one is to read more books and practice, and the other is to have a solid foundation of computer knowledge. If the foundation is not solid, take this opportunity to make up for it.
Reference: www.linuxdiyf.com/bbs/thread-46274-1-1.html