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In all command formats, “[]” indicates optional, and “<>” indicates mandatory

Please point out any omissions

Basic commands

  1. Switch directory

    cd</ Absolute path >For example: CD /home, the absolute path needs to be preceded by a "/"

cd< relative path >Example: CD my_dir

cd -    # return the directory where you were last

cd.Switch to the upper directory

cd ~    # Switch to home directory

cd~< username >Switch to another user's home directory
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  2. File creation, deletion, and file link creation

    Touch < file name >Create an empty fileRm [-f] < file name ># Delete file, add "-f" to indicate no queryLn [options] < source file > [destination file]Create a file linkLn -s < source > [target file]# Create soft linksLn < source file > [target file]Create hard links that cannot point to directories or cross devices
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  3. Create directories, copy directories, and delete directories

    [option] < directory name >Create a directoryCp [-pdria] < source > < destination >The directory must be copied recursively with "-r"Rm -rf < directory name >"R" indicates recursive deletion
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  4. Copies the matched files to the specified directory

    Cp [-pdia] < source file > < destination directory >Copy the code

  5. Obtaining administrator Rights

    su  Switch to user rootSudo < command >Run the command as an administrator
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  6. Creating a New user

    Useradd [option] < username ># add userPasswd < username ># set passwordAdduser < user name >You can also use this command

# delete userUserdel [-fr] < user name ># "f" indicates forcible deletion, and "r" indicates simultaneous deletion of user and home directories
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  7. Switch the user

    Su < username >The root user does not need to authenticate password
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  8. Change directory and file permissions

    Chmod [-r] [xyz] < directory/file ># "-r" recursively changes all files in the directory
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    Permissions can also be set using symbols:

    The command identity options permissions File or directory
    chmod U (User) + (increment) R (read)
    G (group) – (remove) W (write)
    O (Other Users) = (set) X (execution)
    A (All identities)

    Such as:

    chmod u+r g-w o=x test  # add read permission, group member remove write permission, set other users only execute permission
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  9. Change or add a user group

    Groupadd [option] < group name >Create a user groupUsermod [option] < username >Modify user attributesUsermod -g < username ># Change the owning groupUsermod -g < username >Change the extended user group to root, for example, usermod -g rootChown [option][owner][:[group]] < file ># change the file owner and group

# such as:
chown -hR root:test /u  # change owner of all files in /u subdirectory to "root", owner group to "test"
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Other commands

System work command ###Man < command name >View the command manual

echo[string] | $variablesPrint the value of a string or variable at the terminalDate [option][+ specified format]Display and set the system time

reboot  Restart the system

poweroff    # Shutdown systemWget [parameter] < download address ># Used to download network files on the terminal

ps [-aux]   # Check the process status in the system. You can omit the hyphen (-)

top Monitor process activity and system load in real time, similar to task managerPidof [parameter] < process PID>Query the PID of a specified server process

kill[Parameter] < PID>Stop a process. Use it with caution, which may cause the service to exit unexpectedlyKillall [parameter] < process name >Terminates all processes of a specified named service


System status check command ###Ifconfig [network device] [Parameters]Get the nic configuration and network status

uname [-a]  Check the kernel and system version information

uptime  Check the current system load information

free [-h]   Display the current system memory usage informationWho [parameters]# Check the user terminal information of the current login hostLast [parameter]Check the login records of all systems

history [-c]    # Display the executed commands. Add -c to clear the history


Working directory switch command ###
pwd Print the current directoryLs [option] [file]Display information about files in the directory


Text file editing command ###Cat [options] < file ># View plain text content (less content)More [option] < file ># View plain text content (more content)Head [option] < file >View the first N lines of plain text contentTail [option] < file >View the last N lines of plain text content or keep refreshing the contentTr < original character > < target character ># Replace characters in text filesWc [-lwc] < text file ># Count the number of lines, words, and bytes of the specified text

stat< file ># Check the storage information and time of the fileCut [parameter] < file >Extract text content by columnDiff [parameter] < file > < file >Compare the differences between text files
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reference

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