Common Linux Commands

Command operations for Linux

1. Daily Operation Command

* * View your current working directory

Pwd

* * Time to view current system

Date

* * See who is online (who logged in to the server)

Who view current online

Last view recent log in history

2. File System operation

**

LS/view child nodes (folders and files) information in the root directory

Ls-al-a is show hidden file-L is displayed in a more detailed list form

* * Switch Directories

Cd/home

* * Create Folder

mkdir AAA It's a relative path.

Mkdir-p AAA/BBB/CCC

Mkdir/data This is the absolute path of the notation

* * Delete Folder

RmDir can delete empty directory

Rm-r AAA can remove all of the AAA entire folder and all child nodes in it

RM-RF AAA Mandatory Removal AAA

* * Modify folder name

MV AAA Angelababy

* * Create File

Touch somefile.1 Create an empty file

echo "I miss You,my Baby" > Somefile.2 uses the redirection > function to write the output of an instruction to a file, overwriting the original file contents

echo "Huangxiaoming, gun dan" >> somefile.2 append the output of an instruction to a file without overwriting the original file contents

Edit the build file with the VI text editor

Most basic usage

VI somefile.4

1, first will enter the "General mode", this mode only accept a variety of shortcut keys, can not edit the contents of the file

2, press the I key, will be from the general mode into the editing mode, this mode, typed is the file content

3, after editing, press ESC to exit the edit mode, return to the general mode;

4, then press:, enter the "Bottom line command mode", enter the WQ command, carriage return can

Some common shortcut keys

Some useful shortcut keys (used in general mode):

A after the cursor one begins inserting

A in the last insert of the line

I insert at the front of the line

GG jumps directly to the first line of the file

G jump directly to the last line of the file

DD Delete Row, if 5dd, then delete the cursor 5 lines at once

yy copies the current row, copies multiple rows, then 3yy copies the 3 rows near the current row

P Paste

V Enter the character selection mode, select Done, press Y to copy, press p to paste

Ctrl + V into block selection mode, select Done, press Y to copy, press p to paste

Shift+v Enter row selection mode, select Done, press Y to copy, press p to paste

Find and replace (entered in command mode in the bottom line)

%s/sad/88888888888888 effect: Find all sad in file, replace with 88888888888888

/you effect: Find you in the file and navigate to the first found place, press N to navigate to the next matching position (press N to the previous one)

Copy files

CP somefile.1/home/hadoop/

View File Contents

Cat somefile Full output of file contents at once (console)

More Somefile can flip page, scroll down one page (blank) and flip One (b) exit (q)

Less somefile can flip the page, Flip one page (space), flip One (b), flip a line (↑) The next line (↓) can search for keywords (/keyword)

tail-10 Install.log viewing 10 lines at the end of a file

Tail-f Install.log The unique inode number of the small F trace file, even after renaming the file, or tracking the original inode representation of the file

Tail-f Install.log Large F Follow the file name to track

head-10 Install.log View 10 lines of the file header

3. Operation of file permissions

Interpretation of the description format of Linux file permissions

Drwxr-xr-x (can also be represented by binary 111 101 101-755)

D: Identify node type (d: folder-: File L: Link)

R: Readable w: writable x: Executable

The first set of RWX: Represents the permissions of the owner of the file to it: a readable writable executable

The second set of R-x: Represents the permissions of the group to which this file belongs: readable, non-writable, executable

The third group of R-x: Represents the permissions of other users of this file (as compared to the above two categories of users) to it: readable, non-writable, executable

Modify file Permissions

chmod G-RW Haha.dat indicates that the RW permission for the owning group will be Haha.dat canceled

chmod o-rw Haha.dat means to cancel Haha.dat to other people's RW rights

chmod u+x Haha.dat means to increase the haha.dat to the owning user's permissions by x

You can also change the permissions in a digital way

chmod 664 Haha.dat

will be modified into rw-rw-r--.

If you want to uniformly modify all content permissions for a folder, you can use the-r parameter

Chmod-r 770 aaa/

Chown Angela:angela aaa/< only root can perform >

4, the basic user management

Add user

Useradd Angela

To change the password to login

passwd Angela, follow the prompts to enter the password

* * Configure sudo permissions for users

Edit vi/etc/sudoers with Root

Add a line to Hadoop at the following location in the file

Root all= (All) all

Hadoop all= (All) all

Hadoop users can then use sudo to execute system-level instructions

[email protected] ~]$ sudo useradd huangxiaoming

5. System Management operation

View Host Name

Hostname

Modify host name (invalid after reboot)

Hostname Hadoop

Modify host name (permanent after reboot)

Vi/ect/sysconfig/network

Modify IP (invalid after reboot)

Ifconfig eth0 192.168.12.22

Modify IP (permanent after reboot)

Vi/etc/sysconfig/network-scripts/ifcfg-eth0

Mount * * * * mount external storage devices to the file system

Mkdir/mnt/cdrom Create a directory that is used to mount

Mount-t Iso9660-o ro/dev/cdrom/mnt/cdrom/mount the device/dev/cdrom to the mount point:/mnt/cdrom

Umount

Umount/mnt/cdrom

Statistics the size of a file or folder

Du-sh/mnt/cdrom/packages

Df-h to view disk space

Shutdown

Halt

Restart

Reboot

Configure a password-free SSH login between hosts

If A wants to land B

To operate on a:

Percent percent first generate a key pair

Ssh-keygen (when prompted, enter directly)

Percent and then copy and append A's own public key to B's authorization list file Authorized_keys

Ssh-copy-id B

Background service Management

Service Network Status View the state of the specified services

Service network stop stops specifying services

Service network start to start the specified services

Service Network restart restart specified services

Service--status-all View all background services in the system

Setting up a self-starter configuration for background services

Chkconfig View all server self-starter configurations

Chkconfig iptables off turn off automatic start of the specified service

Chkconfig iptables on to start the specified service automatically

System Startup Level Management

Vi/etc/inittab

# Default RunLevel. The runlevels used is:

# 0-halt (do not set Initdefault to this)

# 1-single User mode

# 2-multiuser, without NFS (the same as 3, if you don't have networking)

# 3-full Multiuser mode

# 4-unused

# 5-x11

# 6-reboot (do not set Initdefault to this)

#

Id:3:initdefault:

Command operations for Linux

1. Daily Operation Command
* * View your current working directory pwd
* * Time to view current system date
* * See who is online (who logged in to the server) who view current online last view recent login history

2. File system operation **ls/View child nodes (folders and files) information in the root directory ls-al-a is show hidden file-L is displayed in a more detailed list form
* * Switch Directory Cd/home
* * Create folder mkdir AAA This is the way the relative path is written mkdir-p Aaa/bbb/cccmkdir/data This is the absolute path of the wording
* * Delete folder rmdir can delete empty directory Rm-r AAA can remove AAA entire folder and all child nodes in RM-RF AAA forcibly remove AAA
* * Modify folder name MV AAA Angelababy
* * Create a file touch somefile.1 create an empty file echo "I miss You,my Baby" > Somefile.2 uses the redirection ">" function to write the output of an instruction to a file, overwriting the original file content Echo "Huangxiaoming, gun Dan" >> somefile.2 appends the output of an instruction to a file without overwriting the contents of the original file
Use vi text Editor to edit the generated file ****** the most basic usage VI somefile.41, first will enter the "General mode", this mode only accept a variety of shortcut keys, can not edit the contents of the file 2, press I key, will go from the general mode into the editing mode, this mode, typed is the file content 3, After editing, press ESC to exit the edit mode, return to the general mode, 4, then press:, enter the "command mode", enter the Wq command, return to
Some useful shortcuts (used in general mode): A After the cursor one begins inserting a at the end of the line insert I at the top of the line insert GG directly jump to the first line of the file G jump directly to the last line of the file dd delete line, if 5DD, then the disposable After deleting the cursor 5 lines yy Copy the current line, copy multiple lines, then 3yy, copy the current line near the 3 lines p paste v into the character selection mode, select Done, press Y to copy, press p CTRL + V to enter the block selection mode, select Done, press Y to copy, press p to paste shift+v into the row selection module Select Finish, press Y to copy, press p to paste
Find and replace (enter in the bottom line command mode)%s/sad/88888888888888 effect: Find all sad in file, replace with 88888888888888/you effect: Find the one that appears in the file, and navigate to the first found place, press N to navigate to the next Match position (press N to previous)


Copy file CP somefile.1/home/hadoop/

View the contents of a file cat somefile all output of file contents (console) More Somefile can flip page, scroll down one page (space) up (b) exit (q) Less somefile You can flip a page, flip one (space) up one page (b), flip a line (↑) The next line (↓) can search for keywords (/keyword)
tail-10 Install.log View the file at the end of the 10 lines tail-f install.log small f trace File unique inode number, even if the file renamed, or trace the original inode represents the file Tail-f Install.log Large F follows the file name to track
head-10 Install.log View 10 lines of the file header



3. Operation of file permissions
The description format of Linux file Permissions Drwxr-xr-x (can also be represented by binary 111 101 101-755)
D: Identity node type (d: folder-: File L: Link) r: Readable w: writable x: Performs the first set of RWX: Represents the permissions of the owner of the file to it: Readable writable executable second set of R-x: Represents the permissions of the group to which this file belongs: readable, non-writable, and can perform a third group of R-x : Represents the permissions of other users of this file (as compared to the above two types of users) to it: readable, non-writable, executable

Modify file Permissions chmod G-RW Haha.dat indicates that the RW permission for the owning group will be Haha.dat canceled chmod O-RW haha.dat indicates that the RW permission for the other person will be Haha.dat canceled chmod u+x haha.dat table Add Haha.dat to the permissions of the owning user by adding X
You can also change the permissions in a digital way chmod 664 Haha.dat will be modified to rw-rw-r--
If you want to uniformly modify all content permissions for a folder, you can use the-r parameter chmod-r 770 Aaa/chown Angela:angela aaa/< only root can perform >

4, the basic user management
Add user Useradd Angela to change the password to login passwd Angela Press the prompt to enter the password

* * To configure sudo permissions for users with root edit vi/etc/sudoers in the following location of the file, add a line for Hadoop root all= (All) all Hadoop all= (all) all
Hadoop users can then use sudo to execute system-level instructions [[email protected] ~]$ sudo useradd huangxiaoming

5. System Administration Operation * * * * view hostname hostname**** modify hostname (invalid after reboot) hostname Hadoop
Modify host name (permanent after reboot) vi/ect/sysconfig/network**** modify IP (invalid after reboot) ifconfig eth0 192.168.12.22
Modify IP (permanent after reboot) Vi/etc/sysconfig/network-scripts/ifcfg-eth0

Mount * * * * mount the external storage device to the file system Mkdir/mnt/cdrom create a directory to mount the mount-t iso9660-o ro/dev/cdrom/mnt/cdrom/the device/dev/cdr Om Mount to mount point:/mnt/cdrom
Umountumount/mnt/cdrom

Statistics the size of a file or folder Du-sh/mnt/cdrom/packagesdf-h view disk space * * * shutdown halt**** restart reboot

Configure a password-free SSH login between hosts if A is to log on B to operate on a: percent of the first generation of the key pair Ssh-keygen (prompt, the direct carriage return) percent and then copy and append A own public key to the authorization list file of B authorized_ Keys in Ssh-copy-id B


Background Services Management Service network Status View the state of the specified services service network stop stops specifying service services network start starts the specified services service networ K Restart Restart the specified Services service--status-all View all background services in the system
Set the boot configuration of the background service Chkconfig view all server self-starter configuration chkconfig iptables off automatically start the specified service Chkconfig iptables on to start the specified service automatically

System Boot Level Management Vi/etc/inittab
# Default RunLevel. The runlevels used are:# 0-halt (do not set Initdefault to this) # 1-single user mode# 2-multiuser, without NFS (The same as 3, if you don't have networking) # 3-full multiuser mode# 4-unused# 5-x11# 6-reboot Set Initdefault to this) #id: 3:initdefault:

Common Linux Commands