Linux Common Commands

One, the file directory Operation command

1, CD Description: Change the working directory format: CD [directory name]

Cases:

Cd/home/nadim Enter Absolute path

Cd.. /nadim Entering relative path

CD/Access and Path

CD into the user's home directory

CD ~ Go to User home directory

CD-Returns the directory where it was before entering this directory

2. PWD Description: View the full path to the current working directory.

3. LS Description: Lists all subdirectories and file formats in the target directory: LS [options] [directory name]

Common parameters:

1 Each column displays only one file or directory name.

-A lists all files under the directory, including the. The implied file at the beginning.

-D Displays the directory as if it were a file, rather than displaying the file below it.

-t the LS command option can be sorted in time.

-L lists, in addition to the file name, the permissions, owner, file size, and more

The 1th column: Drwxr-xr-x represents the type and permissions of the file, starting with D as a folder, starting with a file, and starting with the connection file

2nd Column: The number of links to the file.

3rd, 4 columns: Users and Groups with files

5th column: The size of the file.

6th column: The last modification time of the file.

7th column: File name

-r,–recursive listing all subdirectory tiers at the same time

Cases:

# Ls-al |more When there are too many files and directories under the folder, a screen display can be combined with pipe character and more command to achieve split screen display

# LS-LH h parameter combined with L parameter, more reasonable to display the size of the file.

# ls-d * * Only directory information is listed, not files displayed. Sometimes folders under too many files and directories, you can use the-D parameter to display only the directory #ls-r display directory and multi-level subdirectory of the file and directory information #ls-lt sorted by the modified time, the positive sequence display #ls-ltr by the modified time, reverse order display

4, mkdir Description: Set up a directory. mkdir can create a directory and set the directory's permission format: mkdir [-p][--help][--version][-m < directory properties >][directory name]

Cases:

mkdir test1 Create an empty directory

Mkdir-p test2/test22 Create multiple directories recursively

MKDIR-M 777 Test3 Create a directory with permissions of RWXRWXRWX

Mkdir-v test4 Creating a new directory displays information

MKDIR-VP scf/{lib/,bin/,doc/{info,product},logs/{info,product},service/deploy/{info,product}} A command to create a directory structure for a project

5, RM Description: Delete the file or directory, if you want to delete the directory must add the parameter "-r", otherwise the default will only delete the file format: RM [-rf][--help][--version][file or directory ...]

Cases:

Rm-r ml Force Delete Whether the directory is empty, one by one to ask if each folder is deleted;

RM-RF ml do not ask to forcibly delete directories and files

6, rmdir Description: Delete empty directory.

Example: RmDir test1 Delete an empty directory

7. Touch Description: Create this new file. Format: Touch [options] ... File...

8, vi Description: The text editor under Linux (a Add, W save, Q quit, q! do not save the exit, Wq Save, dd delete select row, dw delete the entire word word content).

Cases:

VI FileName: Opens or creates a new file and places the cursor at the beginning of the first

VI +n FileName: Opens the file and places the cursor at the beginning of nth

VI + FileName: Opens the file and places the cursor at the beginning of the last line

VI +/pattern FileName: Opens the file and places the cursor at the first string that matches the pattern

Vi-r filename: A system crash occurred last time you were editing with VI, restore filename VI filename....filename: Open multiple files, edit them sequentially

9. CP Description: Copy file or directory format: CP [-r][source file or directory] [destination file or directory]

10. MV Description: Move or rename an existing file or directory format: MV [-r][source file or directory] [destination file or directory]

11, More/less/cat/tac/head/tail/head Description: Read the file filter on the monitor.

Cases:

Cat 3.txt is serialized out file contents

TAC 3.txt Reverse sequence out of file contents

Head 3.txt lists pre-file content

Head-3 3.txt lists the first three lines of the file

Tail 3.txt lists end-of-file content

Head-3 3.txt Lists the end of the file three lines of content

12, find description: Used in the file tree species to find files, and make the appropriate processing format: Find Pathname-options [-print-exec-ok ...]

Common parameters:

-name finds files by file name.

-perm to find files according to file permissions.

-type find files of a certain type, such as: B-block device files. D-Directory. C-character device file. P-Pipeline file. L-Symbolic link file. F-Normal file.

　　

-amin N Find the last n minutes of access to a file in the system-atime N Find the last n*24 hour Access file in the system

-cmin n Find files in the system that last n minutes were changed file status-ctime N Find the last n*24 hours in the system file status changed

-mmin N Find the last n minutes of the system changed file data files-mtime N Find the last n*24 hours in the system file data changed file

Cases:

Find-atime-2 find the files that have been modified within 48 hours. -name "*.log" finds files that end with. Log in the current directory. ". " Represents the current directory

find/opt/soft/test/-perm 777 Find a file with permission 777 in the/opt/soft/test/directory

Find. -size +1000c-print find files larger than 1K in the current directory

Find. -type f-name "*.log" to find common files that end with a. Log in a directory

13. grep Description: Find the string that matches the condition in the file.

Cases:

The $ grep ' test ' d* shows all the lines in the file that begin with D that contain test.

The $ grep ' test ' AA bb cc Displays the line in the aa,bb,cc file that matches the test.

The $ grep ' [a-z]\{5\} ' AA displays all lines that contain a string of at least 5 consecutive lowercase characters per string.

$ grep ' Wes T.*\1′aa if West is matched, es is stored in memory, labeled 1, and then searched for any character (. *) followed by another ES (\1), which is found to display the row. If you use Egrep or GREP-E, you do not have "\" number to escape, directly written as ' W (es) t.*\1′ on it.

14, WC Description: Statistics Specify the number of bytes in the file, the number of words, lines, and the statistical results display output.

Second, user Rights management

1, Useradd/usermod/userdel/passwd/groupadd Description: User Management

Cases:

Useradd testuser2-g testuser Create a user testuser2 and specify the group TestUser

When adding a user in the/home directory, one more TestUser folder

A line of information is added to the/etc/passwd file

Add user does not specify user group system will default to a group with the same user name

Usermod-g Testg testuser Modify the TestUser group to TESTG

Userdel testuser Delete User when delete user is the/home directory user name folder will not be deleted can delete it manually

passwd testuser Add a password for testuser users

Groupadd Testg Adding groups

2. chmod Description: Rights Management

Example: chmod 755 4 corresponds to 9 bits (111011011) corresponding permission is (RWX-WX-WX)

Third, help class command

1, man Description: Format and display the online Help manual page

2, help description: Most of the commands have a-help option to get instructions for using the command.

Iv. Other

1, Shutdown Description: Shutdown instructions can be closed all programs, and according to the needs of users, to restart or shut down the action. Example: Shutdown now

2 . Clear Description: Clears the terminal screen.

3, Su Description: Change user identity, Su can allow users to temporarily change the identity of the login. Changes must be entered in the user account and password to be changed.

4. Pipeline

s-rl/etc | More '|' is Pipe connector view PPT

5. redirect

s > cmd.txt writes LS results to Cmd.txt wall < cmd.txt

Linux Common Commands