Commands for displaying directories and files

   Ls: Commands for viewing all folders.

   Dir: Commands for displaying specified folders and directories   Tree:  List contents in tree view

   Du: Show directory or file size 


Modify directory, File permissions and owner and array commands

   Chmod: Permission command to change the specified directory or file.

   Chown: Commands for changing file ownership properties.

   Chgrp: Commands for changing file groups.

   Chattr: Used to set that files have permissions that cannot be deleted and modified.

   Lsattr: Hidden properties for displaying files or directories.


Commands for creating and deleting directories

   Mkdir: Used to create a directory

   Rmdir: To delete an empty directory

   Rm -f: Used to delete a directory that is not empty


Create and delete, rename, Commands for copying files

  Touch: Create a new file

   Vi: Create a new file

   Rm: Delete file or directory

   Mv: Commands to rename or move files

   Cp: Copy command

   Scp: Used to copy local files or directories to a remote server

   Wget: Used for downloadftp orhttp Server files to local.


Commands to display the contents of a file

   Cat: Used to display the entire contents of the specified file

   More: Displays the contents of the specified file in pages

   Less: Displays the contents of a specified file in pages, The difference ismore andless Different operation keys for page turning.

   Head: Used to display the front of a filen Row content.

   Tail: After used to display filesn Row content.

   Tail -f: After display file for automatic refreshn Row data content.


Lookup command

   Find: Command to find a specified directory or file.

   Whereis: Find the specified file source and binaries, manuals, etc

   Which: Location used to query commands or aliases.

   Locate: Quick search system <>
<> <>
<> data base <> Specified in.

   Grep: In the specified file or standard output, In standard input, Find what meets the criteria.


Commands to shut down and restart the computer


   Shutdown:-r  Restart immediately after shutdown

             -k  Not really shut down, It's just a warning to all users

             -h  Do not restart after shutdown

   Poweroff: For shutdown and power off

   Init: Change system operation level

        0 Level is used to shut down the system

        1  Level for single user mode

        2 Level is used for multi-user usage mode( But without network function)

        3 Level is used for multi-user usage mode( With network full function)

        4 Level is used for user-defined usage mode

        5 Level indicates entryx  windows Time pattern

        6 Level is used to restart the system

   Reboot:  For computer restart

   Halt: Used to shut down the computer system


Compression and packaging commands

   Tar: For packaging multiple files or directories, But not compression. At the same time, unpack with command

   Gzip: Commands for compressing and decompressing files, The file extension is.gz Ending.

   Gunzip: Used forgzip Compress the document for decompression.

   Bzip2: Used to compress and decompress files or directories

   Bzcat: Use to display the contents of a compressed file.

   Compress/un compress:  compress/ decompression.Z file

   Zcat: Seez orgz Compressed file content at the end.

   Gzexe: Compress executable

   Unarg: decompression.arj file

   Zip/unzip: Compression and file


User operation command

   Su: Toggle user command

   Sudo: A system administrator's identity to execute commands

   Passwd: Password used to modify the user


Change directory and view current directory command

   Cd: Get into <>
<> <>
<> work <> Catalog

   Cd ..: Back to the next level

   Pwd: Display the working directory location of the current user


File connection command

   Ln: Create a connection for the source file, Do not copy the source file, That is, the occupied space is very small.

        It can be divided into software connection and hard link.

        Soft connection: Also known as symbolic connection, Create a shortcut to a file or directory.

Hard link: Give more than one name to a file, Put it in a different directory, User friendly.


Ln The command parameters are as follows:

   -f: When creating a connection, First delete the file or directory with the same name as the destination object.

   -d: Allow system administrators to hard link their own directories.

   -i: Ask the user before deleting a file or directory with the same name as the destination object.

   -n: When creating a soft connection, Treat the target object as a general document.

   -s: Create a soft connection, I.e. symbolic connection.

   -v: Show file or directory names before connecting.

   -b: Backup files that will be overwritten or deleted when connecting.


Help command-----man

<> Other
<> command

   Who: Which users are using in the display system.

        -ami   Show current user

        -u: Show user actions/ work

        -s: Use a short format to display

        -v: Show program version

   Free: View the memory usage of the current system

   Uptime: Shows how long the system has been running

   Ps: Show the dynamics of the transient process

   Pstree: Display all processes in the system in tree mode

   Date: Display or set the date and time of the system.

   Last: Display the user information of login system every month

   Kill:  Kill specific processes

   Logout: Exit system

   Useradd/userdel: Add user/ delete user

   Clear: Clean screen

   Passwd: Set user password



vi editor

    First usevi Command to open a file

Last line mode command:

   :n,m w path/filename  Save the specified scope document( n Table start,m End of table)

   :q!     After modification of the document, forced return

   :q      No changes have been made to the file to exit

   Wq orx   Save exit

   dd   Delete cursor line

   : set number set number

   :n Jump ton That's ok

   :s  Replace string :s/test/test2/g  /g Global replacement / It can also be used.% replace

   / Find string


Commands commonly used in network communication

   Arp: Network address display and control

   ftp: file transfer

   Lftp: file transfer

   Mail: Send out/ Receive email

   Mesg: Allow or deny other users to send information to their own terminals

   Mutt E-mail  Management procedure

   Ncftp : file transfer

   Netstat: Show network connections. Routing table and network interface information

   Pine: outlook express , Browse newsgroups

   Ping: Used to check whether the network is connected smoothly

   Ssh: Remote login in safe mode

   Telnet: Remote login

   Talk: Talk to another user

   Traceroute: Display the path to a host and the time used.

   Wget: Automatically download files from the network
   Write: Other <>
User terminal writes information    Rlogin: Remote login