Linux Common commands

1. Virtual machine Linux Installation and considerations

• Modify boot in BIOS before Linux installation, choose which disk to read system code to boot
• Partition
  • mount point boot file system type EXT4 size 500MB
  • File system type Swap (virtual memory) size (typically 1.5~2 times for physical memory, but not more than 8G)
  • mount point/(root partition) file system type Ext4

Some important directories in the 2.Linux system

• Bin directory: Store frequently used executable files
• Sbin Directory: The executable file that holds the system
• Home directory: Store the user's own files or directories, the root user's home directory is/root, the normal user's home directory in the/home directory, such as the Tom User's family directory is/home/tom
• Dev directory: Device files directory
• ETC Directory: Configuration file directory
• MNT, OPT, media, TMP directory, generally can be used casually

3. Terminal, user, time, help and other related commands

• Switch virtual terminal: ctrl+alt+f[1~6]
• To open a new terminal: Ctrl+shift+n
• Shutdown: Init 0

• System prompt after a normal user logs on: $
• System prompt after the root user logs on: #
• Exit Current User: Exit
• Create User: Useradd user name
  • Useradd-u: Specify UID for user
  • USERADD-G: Specify the group to which the user belongs
  • useradd-d: Specify the user's home directory
  • USERADD-C: Specify user's Notes information
  • Useradd-s: Specifies the shell used by the user
• Delete User: Userdel-r user name
• View user information: ID user name
• To modify user information:
  • Usermod-u: Modifying the UID of a user
  • USERMOD-G: Modifying the user's GID
  • USERMOD-G: Adds a user to the specified group, usermod-g the group name user name. Add the specified group to the user's sub-group, and if you use the command consecutively, the sub-group will overwrite
  • Usermod-ag: Appends a user to the specified group, without overwriting the last joined sub-group
  • Usermod-d: Modifies the user's home directory. Actually modifies the contents of the passwd file, but does not create the modified directory under Home, so you must also manually modify the file
  • Usermod-c: Modify user's Notes information
  • Usermod-s: Modifying the shell used by the user
• Lock User: Usermod-l user name
• Unlock User: Usermod-u user name
• Set Password: passwd set root password, passwd user name settings specify user password
• Switch User: Su-user name
• View current logged in User: WhoAmI
• View all users currently logged on to the system: WHO

• View Date: Date
• Date Modified: Date ' month/day of year '
• View Calendar: Cal
• View calendar for a specified month: Cal month Year
• Sync Hardware time: hwclock-s
• Synchronization system Time: Hwclock-w

• Clear screen: ctrl+l or clear
• Terminate current command: CTRL + C
• View command Help information
  • Man command, Q quit Help manual
  • Command--Help
• Completion command: Tab key

4. Directory Switching and browsing

• Linux command Syntax Format: command "Options" "Parameters"
• Show current directory: PWD
• Go back to the top level directory: CD.
• To the current user's home directory: CD or cd~
• Return to the previous directory: cd-

• Browse directories and files under directory: LS
• Browse the contents of the directory containing hidden files: ls-a
• Browse the current directory for more information: Ls-l or LL
• Browse directories that contain hidden files for more information: Ls-al or Ls-all

5. Create, alias, copy, move, delete

• Create directory: mkdir/directory, e.g. Mkdir/opt/b
• Recursively create a tree structure catalog: mkdir-p/directory 1/Directory 2/directory 3, e.g. Mkdir-p/OPT/DIR1/DIR2/DIR3
• Create file: Touch file name, such as Touch a.txt
  • Touch/test/{1..9}.txt Create 1.txt, 2.txt ..., 9.txt in the test directory
  • Touch/test/{a. Z}.txt Create 26 English-letter txt in the test directory
• Create file under specified directory: Touch/Specify Directory/file name, e.g. Touch/dir1/dir2/a.txt

• View command aliases/aliases: alias command/alias character = ' command '

• Copy file: CP Source path destination path, e.g. cp/opt/a.txt/opt/test/
• Copy file and rename: CP Source path target path new name, for example Cp/opt/a.txt/opt/test/new.txt
• Before the copy overwrite asks: Cp-i, because the CP is the system to cp-i the alias, therefore uses the CP directly, will ask before overwriting. But CP native command location/BIN/CP, using native command will not prompt.
• Recursive replication: cp-r, copy directory and directory files

• Move files or directories: MV Source path Destination Path
• Modify file or directory name: MV Original name New name
• Delete File: RM
• Deleting a file does not use the system hint: rm-f
• Recursive Delete directory: Rm-r
• Deleting any content is not a system hint: RM-RF

6. Write and view the contents of the file

• Write file: Echo ' content ' >> file path
• View File Contents
  • Cat:cat file path
  • Head: Default Displays the first 10 lines of the file, head-n specifies the first n rows of the file to display
  • Tail: Default display of the file after 10 lines of content, tail-n specify the display of the file after n rows of content
  • Tail-f: Dynamically viewing changes to the contents of a file
  • More: View the contents of a file and display it as a percentage, press the ENTER key to page
  • Less: Use the up and down keys to page to view, press the Q key to exit view

Basic use of the 7.vim editor

• Press the A or I key to enter insert mode to modify the file, press ESC to exit the edit
• Press shift+:, enter W save, Q Exit, Wq Save exit, wq! Force save exit

Linux Common commands