LINUX study notes 1--LINUX system commands

1. interface switch: a) enter the character interface: press ctrl + alt + F1: 1. first you need to enter the user login, enter the user name and password, sign: login2. note: F1-F6 is a character interface, so as to achieve multi-task User B) enter the graphical interface: press ctrl + alt + F7c )...

1. interface switching:

 

A) enter the character interface: press ctrl + alt + F1:

 

1. First, you need to log on to the user and enter the user name and password, with the flag: login

 

2. note: The F1-F6 is a character interface to achieve multi-user multitasking

 

B) enter the graphical interface: press ctrl + alt + F7

 

C) the command line statement for program suspension and exit: ctrl + c

 

2. suffix: the suffix after the instruction represents some specific meanings, and each instruction is different.

 

A)-r: Directory operations

 

B)-f: No reminder, indicating forced

 

C)-I: Set a reminder for the operation

 

D)-p: you can create multiple layers.

 

E)-a: indicates an implicit file.

 

3. configuration command: alias can configure the command itself

 

A) [root @ pact ~] # Alias

 

A) alias cp = 'CP-I'

 

A) alias l. = 'ls-d. * -- color = tty'

 

A) alias ll = 'ls-l -- color = tty'

 

A) alias ls = 'ls -- color = tty'

 

A) alias mv = 'MV-I'

 

A) alias rm = 'rm-I'

 

A) alias vi = 'vim'

 

A) alias which = 'Alias |/usr/bin/which -- tty-only -- read-alias -- show-dot -- show-tilde'

 

A) [root @ pact ~] #

 

4. user differentiation: the superuser is #, and the common user is $

 

A) Super User: root

 

5. add User: useradd user name

 

A) the corresponding user directory will be added to the home directory.

 

6. change user password: passwd user name

 

7. Switch User: su user name

 

A) a super user switches to a common user without a password,

 

B) a password is required for normal users to switch to other users.

 

8. shut down: shut down

 

9. copy the file: space in the target position of the cp Source File

 

A) the source file should be a file in the current directory.

 

B) the target location should be specific: otherwise, it is under the current directory by default. if it is under the current directory, it is considered to be renamed.

 

10. copy Directory: space in the target position of the cp-r source file

 

A) only copy all the files in the folder without folders

 

11. move: a space in the middle of the target location of the mv source file

 

A) the target location should be the specific address; otherwise, the name will be changed.

 

12. change the name: a space in the middle of the target name of the mv source file name

 

13. delete: rm

 

A) delete the directory: rm-r

 

B) delete files without notice. force delete: rm-f

 

14. Directory:

 

A) create a directory: mkdir

 

B) create multiple sub-directories: mkdir-p

 

C) change the working directory: cd

 

D) return to the original Directory: cd-

 

E) view the current path: pwd

 

15. File:

 

A) display directory File: ls

 

B) display the hidden File: ls-

 

C) change the file to an implicit File: change the file name and add it to the front.

 

16. Packaging: Packaging and compression

 

A) file suffix: Package File:. tar compressed file:. gz

 

B) packaging: files whose names need to be packaged after tar cvf packaging

 

1. C indicates creation, v indicates details, and f indicates files. you can use man to understand the specific usage of commands.

 

C) unpack: tar xvf

 

D) package compression: tar cvzf

 

E) decompress the package: tar xvzf

 

F) decompress: unzip

 

17. file access permissions

 

A) permission for displaying files: ls-l

 

B) there are three different types of users who can access files or directories: File owners, users in the same group as the owner and other users. The owner is generally the creator of the file.

 

C)-rw-r -- 1 root 483997 Ju1 l5 17: 3l sobsrc. Tgz

 

D) note that there are 10 locations in total. The first character specifies the file type. if the first character is a horizontal line, it indicates a non-directory normal file. Each of the nine characters after a group of Three Represents the permissions of the three types of users. If it is d, it indicates a directory. R indicates read-only, w indicates write, x indicates executable, and x indicates that this permission is not granted.

 

E) change permission: chmod [who] [+ |-| =] [mode] file name

 

1. u indicates the file owner.

 

2.g indicates the users in the same group as the file owner.

 

3. o indicates "other users ".

 

4. a indicates "all users ". It is the default value of the system.

 

5. + add a permission

 

6.-cancel a permission.

 

7. = Grant the given permission

 

18. View space usage

 

A) View disk usage: df

 

B) View disk usage in kb: df-k

 

C) view the directory usage: du

 

D) view the directory usage in B: du-B

 

19. network configuration: Only super users can do this.

 

A) configure the IP address: ifconfig eth0 192.168.0.1

 

B) disable the eth0 Nic: ifconfig eth0 down

 

C) restore the eth0 Nic: ifconfig eth0 up

 

20. view the network status: netstat

 

A) view all network listening ports in the system: netstat-

 

21. software installation

 

A) install the file named "tftp": rpm-ivh tftp. rpm

 

B) list all installed rpm packages: rpm-qa

 

C) uninstall the rpm package named "rpm-e name"

 

22. Mount: The file is stored in a directory in LINUX, which is generally in the mnt directory.

 

A) mount the optical drive to the/mnt Directory: mount/dev/cdrom/mnt

 

B) cancel mounting the optical drive to/mnt: umount/mn

 

23. search for files:

 

A) there are spaces between the find path-name'filename '.

 

B) Fuzzy search: find the file "find.-name 'co * '" starting with "co" in the current directory and its subdirectories *'

 

C) exact search: find the file named test in the current directory and its subdirectories: find.-name 'test'

 

24. search for strings:

 

A) in the current directory and its subdirectories, find the file containing the file string: grep "file".-rn

 

B) view all ports used for tftp: netstat-a | grep tftp

 

25. dynamically view CPU usage: top

 

26. View processes: View all processes in the system: ps aux

 

27. kill process: kill-s SIGKILL 4096

 

28. help: man

 

29. computing program Running time: time. file name

 

30. view the current time: date

 

From the column of Ainemo