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What are the linux commands? for this question, this article introduces the corresponding analysis and answers in detail, hoping to help more partners who want to solve this problem to find a more simple and easy way.

I. Management of the file system

Tips: when entering commands, you should use the tab key to complete.

Ls to view directory information (ls /)

Ls-l is equivalent to ll.

Pwd to view the current path

Cd switch directory (cd /), if there are no parameters, switch to user home directory ~

Mkdir create folder

Rmdir deletes empty folders (only empty folders can be deleted)

Rm-r / a ram b (delete a non-empty folder)

Create a file

Touch a.avi creates an empty file

Vi blabla.txt edits a file with a text editor and saves

Echo "angelababy,zhen de hen xihuan ni" > qingshu.txt put the output on the left into the file on the right

Delete a file

Rm filename (rm-r delete folder rm-rf force deletion of files or folders)

Move the file to change the file name

Mv a/wenjian1.txt b/file1.txt (changes the file name while moving the file)

Copy a file

Cp srcFile destFile

View the contents of the file

Cat wodeqingshu.txt

More wodeqingshu.txt can be viewed in pages.

Less wodeqingshu.txt not only can be paged, but also can easily search, flip back and other operations.

Tail-10 wodeqingshu.txt View the 10 lines at the end of the file

The log printed by the program is of extraordinary debug significance in production practice.

Tail-f user.log refreshes the tail of the display file in real time

Head-20 wodeqingshu.txt View the first 20 lines of the file

II. Authority management

Drwxrwxr-x

Modify permissions

Chmod u+rwx file adds or removes the permissions of its users for file

(U on behalf of user o, on behalf of other users g, on behalf of members of the group)

Chmod 567file can also represent permissions with numbers

5-> 101-> rmurx

Modify the owner of the file owner

Chown hadoop:hadoop file changes the owner of file to hadoop user and the group he belongs to to hadoop group

The permissions of the parent directory also have restrictions on the operation of files or folders at the same level.

III. User management

Add user

Useradd itcast0830

You must set a password to log in to passwd itcast0830 properly

Delete user

Userdel yun12

Userdel-r itcast-Delete the user's home directory while deleting the user

Modify user properties

Usermod-l b a changes the login name of a to b

Usermod-g hadoop itcast0830 changes the itcast0830 group to the hadoop group

Usermod-G hadoop,root itcast0830 adds two groups hadoop,root to itcast0830

Usermod-d / home/itcast itcast0830 changes the home directory of itcast0830 to / home/itcast

(create the itcast directory in advance and copy the environment variable file)

-modify the user's password

Passwd itcast0830

Add a user group

G

Roupadd beauties

Delete a user group

Groupdel beauties

Modify user group properties

Groupmod

View the identity of the current login

Whoami

View the groups that are currently in use

Groups

Fourth, common system management (when it comes to modification, be sure to use root permissions)

****

Easily do not use su to switch to the identity of root

Ordinary users use sudo to execute commands for root permissions

For example, add hadoop users to the sudoers file

Root ALL= (ALL) ALL

Hadoop ALL= (ALL) ALL

Disk space information view

Df-h view disk space status information

Du-sh * View the summary size of all subdirectories and files under the current directory

Process information view

Free to check memory usage

Top to view the system process information refreshed in real time

Ps-ef to view snapshots of process information in the current instant in the system

Ps-ef | grep myshell.sh searches myshell process information

Kill-9 pid kills the process (- 9 means forced kill)

5. File archiving compression (1: packaging-archiving; 2: compression)

1. Filing

Tar-cvf testdir.tar testdir/

2. Compression

Gzip testdir.tar

Gzip file

Bzip file

Tar-czvf testdir.tar.gz testdir/

Extract tar-xzvf testdir.tar.gz to the current directory

Tar-zxvf testdir.tar.gz-C Downloads/ is extracted to the specified Downloads directory

VI. Network management

Modify the configuration of the ip address

Vi / etc/sysconfig/network-scripts/ifcfg-eth0 can change the ip address by modifying the configuration file

Or use the setup instruction to modify it through a pseudo graphical interface with prompts.

View ip addr

Ifconfig

Modify hostname

Vi / etc/sysconfig/network modifies the hostname configuration item in it

To take effect immediately, you can execute the instruction hostname nidezhujiming.

HOSTNAME=yun12-01

Manage the hostname of the private network-ip address mapping

Vi / etc/hosts

192.168.2.250 yun12-01

Restart network services

Service network restart under root permission

Turn off the firewall service service iptables stop

Turn off the firewall and start chkconfig iptables off automatically

Modify the default startup level of the system

Vi / etc/inittab

# 0-halt (Do NOT set initdefault to this)

# 1-Single user mode

# 2-Multiuser, without NFS (The same as 3, if you do not have networking)

# 3-Full multiuser mode

# 4-unused

# 5-X11

# 6-reboot (Do NOT set initdefault to this)

#

Id:3:initdefault:

~

Start the full-function character interface with level 3

View the information about the current process connecting to the network

Netstat-nltp

Common tool instructions

Wc statistics text information (lines, words, characters)

Date and time when date views or modifies the system

Echo outputs the value of a string or variable

The most common text editor in vi linux system

VI. Software installation in linux

Jdk

Unpack the installation package to your installation path

Then modify the environment variable sudo vi / etc/profile

Then source / etc/profile will take effect.

Tomcat

Eclipse

Mysql

Redhat's RPM package management is also a commonly used package manager.

Rpm-qa | grep mysql

Sudo rpm-e mysql-libs-5.1.66-2.el6_3.i686-- nodeps

Sudo rpm-ivh MySQL-server-5.1.73-1.glibc23.i386.rpm

The answers to the questions about the linux command are shared here. I hope the above content can be of some help to you. If you still have a lot of doubts to be solved, you can follow the industry information channel to learn more about it.

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