Linux Common Command Description

1. Basic shortcut key Usage

CTRL + C: Stop process

CTRL + L: Clear screen

CTRL + R: Search History commands

CTRL + Q: Exit

2. Common directory or folder commands

Description: When installing Linux, create a itcast user and then log into the system using the root user

1. Go to the user root directory

CD ~ or CD

2. View your current directory

Pwd

3. Go to the Itcast user root directory

CD ~itcast

4. Return to the original directory

CD-

5. Go back to the top level directory

Cd..

6. View all files under the Itcast user's root directory

-A is an explicit hidden file-L is displayed in a more detailed list
Ls-la

7. Create a Itcast folder in the root directory

Mkdir/itcast

8. Create SRC and webroot two folders under the/itcast directory

Created separately: MKDIR/ITCAST/SRC
Mkdir/itcast/webroot
Create simultaneously: Mkdir/itcast/{src,webroot}

9. Folder Permission Description

Ls-ld/tmp

The permission value of DRWXRWXRWT is 1777

3. File commands 1. view file Details

Stat A.txt

2. Mobile

MV a.txt/ect/
Renamed
MV B.txt A.txt
Move and rename
MV A.txt. /b.txt

3. Copy and rename

CP A.txt/etc/b.txt

4.VI undo Changes

CTRL + U (undo)
Recovery
CTRL + R (Redo)

5. Use > To create a struts.xml

> Struts.xml

6. Create multiple files with touch

Touch A.txt B.txt
Touch/home/{a.txt,b.txt}

7. Create a file using Echo

Create a Test.txt file under the/itcast directory and write the content "This is test"

echo "This is Test" > Test.txt

Append write to Readme file "Please read Me first"
echo "Please read Me first" >> README

8. Copy file contents using Cat

Copy the contents of one file into another file
Cat A.txt > B.txt
Append content
Cat A.txt >> B.txt

Note the:>, Touch, Echo, and cat comparisons to file operations

①> can only create a single file;

②touch can create single or multiple files, unable to insert content into files;

③echo creates a file and inserts a line of string into the file, manipulating a single-line string;

④cat creates a file and inserts all the contents of another file into the new file, manipulating the entire file.

9. Take a look at the contents of Test.txt

Cat Test.txt
More Test.txt
Less test.txt

Note: More or less is paged view

10.CP Copy specific files

Copy all Java language programs to the finished subdirectory:
CP *.java finished

11.RM Delete a specific file

Delete the file with the Java extension in the current directory
Rm-f *.java

Delete Empty Directory
RmDir

12.WC Statistics File

See how many words the Readme file has, how many fewer lines
Wc-w README
Wc-l README

13.VI Editing file contents

VI Somefile.txt

① first enters the "General mode", which accepts only a variety of shortcut keys and cannot 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 is complete, press ESC to exit the edit mode and return to the general mode;
④ Press:, enter the "Bottom line command mode", enter the Wq command, return to

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)

4. File and folder permissions command 1.linux file Permissions description format interpretation

Drwxr-xr-x (can also be expressed in decimal notation 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

2. Grant owner u, owning Group G, and other user o permissions to the file

chmod ug+w,o-w a.txt b.txt indicates that a.txt, B.txt is set to its owner and that the group can be written to, but other people are not writable

chmod a+wx C.txt says to set the C.txt file to everyone can write and execute

Chmod-r a+r/itcast means that all files and subdirectories in the/itcast directory are set to anyone who can read

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

5. Set up users and user groups

The owner of all files and subdirectories under the/itcast directory is set to root, and the user has a group of users
Chown-r Root:users/itcast

Sets all files in the current directory and subdirectories to Itcast, set to users
Chown-r Itcast:users *

Note: -R means recursive execution, recursive execution on files and directories

5. Find a command 1. Find an executable command

which LS

2. Find the location of the executable commands and help

Whereis ls

3. Find files (need to update Library: updatedb)

Locate Hadoop.txt

4. Start a search from a folder

Find/-name "hadooop*"
Find/-name "hadooop*"-ls

5. Find and delete

Find/-name "hadooop*"-ok rm {} \;
Find/-name "hadooop*"-exec rm {} \;

6. Find files for Hadoop for users

Find/usr-user Hadoop-ls

7. Find the file that the user is Hadoop and (-a) has a group root

Find/usr-user hadoop-a-group Root-ls

8. Look for a file with a user who has a group root and is a folder type for Hadoop or (-O)

Find/usr-user hadoop-o-group root-a-type D

9. Find a file with a permission of 777

Find/-perm-777-type D-ls

10. Show Command History

History

11.grep

grep Hadoop/etc/password

6. Packaging and Compression 1.gzip decompression

Compression
Gzip A.txt

Extract
Gunzip a.txt.gz
Gzip-d a.txt.gz

2.BZIP2 Decompression

Compression
Bzip2 A

Extract
BUNZIP2 a.bz2
Bzip2-d a.bz2

3.tar Decompression

Package the files of the current directory to compress
TAR-CVF Bak.tar .
Append the/etc/password file to the Bak.tar (R)
TAR-RVF Bak.tar/etc/password

Extract
TAR-XVF Bak.tar

4.tar.gz Decompression

Package and Compress gzip
TAR-ZCVF a.tar.gz

Unzip
TAR-ZXVF a.tar.gz
Unzip to the/usr/.
TAR-ZXVF a.tar.gz-c/usr

Viewing the contents of a compressed package
TAR-ZTVF a.tar.gz

5.TAR.BZ2 Decompression

Package and compress into bz2
TAR-JCVF a.tar.bz2

Decompression bz2
TAR-JXVF a.tar.bz2

6.zip Decompression

Zip/unzip

7. Regular expression commands 1. Find and cut-split intercept

Cut intercept to: divide and hold the seventh paragraph
grep hadoop/etc/passwd | Cut-d:-f7

2. Sorting sort

Du | Sort-n

3. Queries that do not contain Hadoop

Grep-v hadoop/etc/passwd

4. Regular expression contains Hadoop

grep ' Hadoop '/etc/passwd

5. Regular expression (dots represent any one character)

grep ' H.*p '/etc/passwd

6. Regular expression begins with Hadoop

grep ' ^hadoop '/etc/passwd

7. Regular expressions End with Hadoop

grep ' hadoop$ '/etc/passwd

Rules:
. : any one character
A *: Any number of a (0 or more a)
A? : 0 or one A
A +: one or more a
. *: Any number of arbitrary characters
\. Escape.
\O\{2\}: o repeat two times

grep ' ^i.\{18\}n$ '/usr/share/dict/words

Find lines that do not start with #
Grep-v ' ^# ' a.txt | Grep-v ' ^$ '

Starting with H or R
grep ' ^[hr] '/etc/passwd

Not starting with H and R.
grep ' ^[^hr] '/etc/passwd

Not starting with H to R.
grep ' ^[^h-r] '/etc/passwd

8. Input and output redirection and piping 1. Create a new file

Touch A.txt
> B.txt

2. Error redirection:2>

Find/etc-name zhaoxing.txt 2> Error.txt

3. Enter the correct or incorrect information into the Log.txt

Find/etc-name passwd > /tmp/log.txt 2>&1
Find/etc-name passwd &> /tmp/log.txt

4. Append>>5. Convert lowercase to uppercase (input redirection)

TR "A-Z" "A-Z" </etc/passwd

6. Automatically create files

Cat > Log.txt << EXIT
> CCC
> DDD
> EXI

7. See how many files are in/etc

Ls-l/etc/| grep ' ^d ' | Wc-l

8. See how many files are in/etc, and enter the file details into the Result.txt

Ls-l/etc/| grep ' ^d ' | Tee Result.txt | Wc-l

9. User and Group command 1. Add a Tom user, set it to belong to the Users group, and add comment information

Step through: Useradd Tom
Usermod-g users Tom
Usermod-c "HR Tom" Tom
One-Step completion: Useradd-g users-c "hr Tom" Tom

2. Set the Tom User's password

passwd Tom

3. Add a Jerry user and set a password

Useradd Jerry
passwd Jerry

4. Change Tom User's login name to Tomcat

Usermod-l Tomcat Tom

5. Add tomcat to the SYS and root groups

Usermod-g Sys,root Tomcat

6. View the group information for Tomcat

Groups Tomcat

7. Add a America Group

Groupadd America

8. Add the Jerry user to the America Group

Usermod-g America Jerry

9. Remove the Tomcat user from the root group and the SYS group

gpasswd-d Tomcat Root
gpasswd-d Tomcat SYS

10. Change the America group name to AM

Groupmod-n am America

10. System commands 1. View Host Name

Hostname

2. Modify hostname (invalid after reboot)

Hostname Hadoop

3. Change the hostname (permanent after reboot)

Vi/ect/sysconfig/network

4. Modify IP (invalid after reboot)

Ifconfig eth0 192.168.12.22

5. Modify IP (permanent after reboot)

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

6. View System Information

Uname-a
Uname-r

7. View ID Command

Id-u
Id-g

8. Date

Date
Date +%y-%m-%d
Date +%t
Date +%y-%m-%d ""%T

9. Calendar

Aa.

Cal 2012

10. View file Information

File filename

11. Mount the hard drive

Mount
Umount
Load Windows share
Mount-t CIFS//192.168.1.100/tools/mnt

12. View File Size

Du-h
Du-ah

13. View Partitions

Df-h

14. View Memory usage

Free

15. View the file system

/proc

16.ssh

SSH [email protected]

17. Turn off the machine

Shutdown-h Now/init 0
Shutdown-r Now/reboot

11. Process Control commands 1. View the user's most recent login status

Last
Lastlog

View current Online
W.H.O.

2. View the System log

ls/var/log/

3. Check the system error log

Tail/var/log/messages

Tail-f/var/log/messages

Tail-f/var/log/messages

4. View the process

Top

5. End Process

Kill 1234
Kill-9 4333

Linux Common Command Description