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| = Common Commands with examples =
| | A place to get started to understand Linux commands and tools |
| These commands and their usage are used for both the LinuC Level 1 Exam 101 and Exam 102. Using these commands in various scenarios to become proficient in basic command-line tasks, file management, and system administration.
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| == ls - List directory contents ==
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| The ls command is used to list files and directories in a specified location. It has many options to customize the output.
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| Examples:
| | * [https://matomo.mintarc.com/mediawiki/index.php?title=Common_Commands_with_examples Common Commands ] |
| *ls -l: Long listing format, showing permissions, owner, size, and modification date | | * [https://matomo.mintarc.com/mediawiki/index.php?title=SSH_Stuff SSH Stuff] |
| *ls -a: Show all files, including hidden ones (those starting with a dot)
| | * [https://matomo.mintarc.com/mediawiki/index.php?title=Create_monitor_and_terminate_process Create, monitor and terminate process] |
| *ls -R: Recursively list subdirectories
| | * [https://matomo.mintarc.com/mediawiki/index.php?title=SystemD_Stuff SystemD Stuff] |
| *ls -lh: Use human-readable file sizes (e.g., 1K, 234M, 2G)
| | * [https://matomo.mintarc.com/mediawiki/index.php?title=Desktop_environment Desktop Environment] |
| *ls /etc: List contents of the /etc directory
| | * [https://matomo.mintarc.com/mediawiki/index.php?title=Directory_Manipulation_and_Management Directory Manipulation and Management] |
| | | * [https://matomo.mintarc.com/mediawiki/index.php?title=Perform_basic_file_management Perform basic file management] |
| == cd - Change directory ==
| | * [https://matomo.mintarc.com/mediawiki/index.php?title=Hard_and_symbolic_links_Weight Hard and symbolic links Weight] |
| cd is used to navigate the file system. It can use absolute or relative paths.
| | * [https://matomo.mintarc.com/mediawiki/index.php?title=File_placement_and_search File placement and search] |
| | | * [https://matomo.mintarc.com/mediawiki/index.php?title=Process_text_stream_with_filters Process text stream with filters] |
| Examples:
| | * [https://matomo.mintarc.com/mediawiki/index.php?title=Use_streams,_pipes_and_redirects Use streams, pipes and redirects] |
| *cd /home/user: Change to the /home/user directory (absolute path) | | * [https://matomo.mintarc.com/mediawiki/index.php?title=Search_text_files_using_regular_expressions Search text files using regular expressions] |
| *cd ..: Move up one directory level
| | * [https://matomo.mintarc.com/mediawiki/index.php?title=Perform_basic_file_edits_using_an_editor Perform basic file edits using an editor] |
| *cd -: Return to the previous directory
| | * [https://matomo.mintarc.com/mediawiki/index.php?title=Repository_and_Package_Management Repository and Package Management] |
| *cd ~: Change to the user's home directory
| | * [https://matomo.mintarc.com/mediawiki/index.php?title=Debian_package_management Debian package management] |
| *cd Documents/Projects: Change to a subdirectory (relative path)
| | * [[Linux_Kernel|The Linux Kernel]] |
| | | * [[Init_Systems|Explaining Init Systems]] |
| == pwd - Print working directory == | | * [[Linux_Virtual_Machines|Linux Virtual Machines]] |
| pwd displays the full path of the current working directory.
| | * [[Mmdebstrap|mmdebstrap]] |
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| Examples:
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| *pwd: Outputs something like /home/user/Documents | |
| *pwd -P: Print the physical directory, without any symbolic links
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| == mkdir - Create a new directory ==
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| mkdir is used to create one or more directories.
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| Examples:
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| *mkdir newdir: Create a directory named "newdir" | |
| *mkdir -p parent/child/grandchild: Create nested directories
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| *mkdir dir1 dir2 dir3: Create multiple directories at once
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| *mkdir -m 755 secured_dir: Create a directory with specific permissions
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| == touch - Create an empty file or update file timestamps ==
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| touch can create empty files or update the access and modification times of existing files.
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| Examples:
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| *touch newfile.txt: Create a new empty file or update timestamps if it exists
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| *touch -t 202502191200 file.txt: Set specific timestamp (YYYYMMDDhhmm)
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| *touch -r reference_file target_file: Use timestamps from reference_file | |
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| == cp - Copy files and directories ==
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| cp is used to copy files and directories from one location to another.
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| Examples:
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| *cp file.txt /home/user/backup/: Copy a file to another directory
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| *cp -r dir1 dir2: Copy a directory and its contents recursively | |
| *cp -i *.txt /destination/: Copy all .txt files, prompting before overwrite
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| *cp -p source dest: Preserve file attributes (mode, ownership, timestamps)
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| == mv - Move or rename files and directories == | |
| mv can move files/directories or rename them.
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| Examples:
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| *mv file.txt newname.txt: Rename a file | |
| *mv /home/user/doc.txt /tmp/: Move a file to another directory
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| *mv dir1 dir2: Rename a directory (if dir2 doesn't exist) or move dir1 into dir2 | |
| *mv -i *.jpg /home/user/Pictures/: Move all .jpg files, prompting before overwrite
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| == rm - Remove files or directories ==
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| rm is used to delete files and directories. Use with caution!
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| Examples:
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| *rm file.txt: Delete a file | |
| *rm -r directory/: Recursively remove a directory and its contents
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| *rm -f unwanted_file: Force removal without prompting
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| *rm -i *.log: Remove .log files with confirmation for each
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| == rmdir - Remove empty directories == | |
| rmdir is used to remove empty directories.
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| Examples:
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| *rmdir empty_folder: Remove an empty directory | |
| *rmdir -p parent/child/grandchild: Remove nested empty directories
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| == ssh - Secure Shell for remote system access ==
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| sh is used to securely log into remote systems, execute commands on remote machines, and create encrypted tunnels for various network services.
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| Examples:
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| *ssh user@example.com: Connect to example.com as "user"
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| *ssh -p 2222 user@example.com: Connect using a non-standard port (2222) | |
| *ssh -i ~/.ssh/my_key user@example.com: Use a specific private key for authentication
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| *ssh user@example.com 'ls -l /tmp': Execute a command on the remote system without entering interactive mode
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| *ssh -X user@example.com: Enable X11 forwarding for GUI applications
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| == scp - Secure Copy for file transfer == | |
| scp uses SSH to securely copy files between local and remote systems or between two remote systems.
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| Examples:
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| *scp file.txt user@example.com:/home/user/: Copy a local file to a remote system | |
| *scp user@example.com:/home/user/file.txt .: Copy a remote file to the local system
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| *scp -r directory/ user@example.com:/home/user/: Recursively copy a directory to a remote system | |
| *scp -P 2222 file.txt user@example.com:/home/user/: Use a non-standard SSH port
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| *scp user1@host1:/file user2@host2:/directory/: Copy a file from one remote host to another | |
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| == ssh-keygen - Generate SSH key pairs ==
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| ssh-keygen creates public/private key pairs for SSH authentication, offering a more secure alternative to password-based logins.
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| Examples:
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| *ssh-keygen -t rsa: Generate an RSA key pair
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| *ssh-keygen -t ed25519: Generate an Ed25519 key pair (more secure and efficient)
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| *ssh-keygen -t rsa -b 4096: Generate an RSA key with 4096-bit strength | |
| *ssh-keygen -f ~/.ssh/my_key: Specify a custom filename and path for the key
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| *ssh-keygen -p -f ~/.ssh/id_rsa: Change the passphrase of an existing private key
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| == ssh-copy-id - Install SSH key on a remote server ==
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| ssh-copy-id securely copies your public key to a remote server's authorized_keys file, enabling key-based authentication.
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| Examples:
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| * ssh-copy-id user@example.com: Copy the default public key to the remote server | |
| * ssh-copy-id -i ~/.ssh/my_key.pub user@example.com: Specify a particular public key to copy | |
| * ssh-copy-id -p 2222 user@example.com: Use a non-standard SSH port | |
