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IntroductionIf you’re new to Linux or have recently switched to it, you may have been overwhelmed by the vast array of commands you can use within it.
These commands have a different syntax than those you might be used to in Windows or Mac systems; however, once you have an understanding of how they work, using Linux commands becomes easy.
In this article, we’ll provide you with a comprehensive guide on complex Linux commands.
We’ll explain what they are, how they work, and how you can use them to optimize your work processes. Let’s get started!
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What are Linux Commands?Linux commands are text-based instructions that you can use within a Linux terminal. They can help you to execute specific tasks and communicate with your computer’s operating system. The terminal is a text-based interface that you can access by typing in specific commands. You can achieve several tasks, such as copying files, starting programs, or updating your system, using only commands.
Basic Linux CommandsLet’s begin with some basic commands. These commands are used frequently and are an essential part of mastering the Linux terminal.
ls: This command lists all the files and directories in your current location. You can use the -a option to display hidden files, and the -l option to display them in long format.cd: The cd command is used to change directories. For example, cd Downloads will take you to the Downloads directory.pwd: This command displays the working directory in your terminal.mkdir: The mkdir command is used to make a new directory. For example, to create a folder called ‘test’, you can use the command mkdir test.rm: The rm command is used to remove files, and it’s often used with the -rf option to remove directories.cp: This command is used to copy files and directories from one location to another.mv: This command is used to move files and directories from one location to another.Intermediate Linux CommandsNow that you are familiar with some basic Linux commands let’s look at a few intermediate level commands to enhance your Linux knowledge.
grep: This command is used to search for a specific word or pattern within a file. For example, to look for the word ‘example’ in a file called ‘file.txt’, you can run the command grep example file.txt.find: The find command is used to search through a directory’s contents recursively. You can use it with different options such as -name to specify filenames or -size to search for specific file sizes.ps: The ps command lets you view the currently running processes on your system. You can use it with different options such as -ef to display all processes.wget: The wget command lets you download files from the internet. For example, to download a file called test.txt, you can use wget https://www.example.com/test.txt.Advanced Linux CommandsHere are few advanced Linux commands that are rarely used but can be helpful in certain situations.
dd: The dd command is used to copy and convert data. For example, to create a bootable USB drive using an ISO file, you can use the command sudo dd if=path/to/iso of=/dev/sdb bs=4M; sync. Make sure to use the correct input and output file locations.tar: The tar command is used to create compressed archives. For example, to create a .tar.gz archive of all files in the current directory, you can use the command tar -czvf archive_name.tar.gz *.awk: The awk command is used to manipulate text files. For example, to print the first column of a tab-separated values file, you can run the command awk -F’\t’ ‘{print $1}’ file.txt.Security-focused Linux CommandsLinux commands are powerful tools that can be used to perform various security-focused tasks such as user management, file permissions, and network security. In this section, we will take a look at some of the most commonly used security-focused Linux commands.
chmod: This command is used to change the permissions of a file or directory. The permissions can be specified using a numerical code or a symbolic code.passwd: This command is used to change the password of a user account. The user is prompted to enter their old password, followed by their new password.sftp: This command is used to securely transfer files over the network. It uses the SSH protocol to encrypt the data being transferred.iptables: This command is used to manage network security by setting up rules for incoming and outgoing traffic. It can be used to block specific IP addresses or protocols.ssh: This command is used to establish a secure remote connection to another computer. It uses the SSH protocol to encrypt the data being transferred.By using these security-focused Linux commands, you can help protect your computer and network from potential security threats.
Tips of Linux commandMy journey with Linux commands has been both challenging and rewarding, and I’ve picked up several tips along the way that have been instrumental in my learning process.
Initially, understanding the basic structure of Linux commands seemed daunting, but as I delved deeper, it became second nature.
I remember the first time I successfully used a command with its options and arguments; it felt like a significant achievement.
The man pages were my constant companions, offering detailed insights whenever I encountered unfamiliar commands.
They were like a guiding light, illuminating the path in the often murky world of command-line syntax.
One of the most practical skills I acquired was mastering tab completion.
This simple effective tool saved me countless hours that I might have otherwise spent typing out long file names or correcting typos.
It was a small revelation, making my command-line interactions smoother and more efficient.
Each of these experiences has not only bolstered my technical skills but also deepened my appreciation for the versatility and power of Linux.
The journey through the world of Linux commands is ongoing, and each new tip or trick I learn opens up further possibilities and efficiencies.
Here are some tips and best practices for using Linux commands effectively:Understand the Basic Structure of Commands: Most Linux commands follow the structure: command [options] [arguments]. Understanding this structure helps in effectively using any command.Use the Man Pages: For any command, you can view its manual page using man [command]. This is a great way to learn about what a command does, its options, and how to use it.Tab Completion: Use the Tab key for auto-completing commands and file names. This saves time and reduces typos.Use Wildcards: Wildcards like * (matches any number of characters) and ? (matches a single character) are very useful in commands to match filenames and patterns.Redirect Output and Errors: Learn to redirect output using > and >> and errors using 2>. For example, ls > files.txt saves the output of ls to files.txt.Piping: Use pipes (|) to use the output of one command as the input to another. For example, ls -l | grep “txt” will list files and then filter only those containing “txt”.Learn Key Shortcuts: For example, Ctrl + C to stop any command, Ctrl + Z to suspend any command, and Ctrl + R to search through your command history.Use grep for Searching: grep is a powerful tool for searching text in files or output. It’s very useful for filtering information.Chain Commands: Use && to execute a command only if the previous command was successful. For example, cd /var/log && ls will list files in /var/log only if the cd command succeeds.Use sudo Wisely: sudo allows you to run commands with administrative privileges. Be cautious with it, especially when executing scripts or commands from untrusted sources.Explore find and locate: These commands are incredibly useful for finding files and directories. find searches in real-time, while locate uses a database updated by updatedb.Customize Your Shell: Learn to customize your shell with .bashrc or .bash_profile for Bash. You can set aliases for commands, change the prompt, and more.Use history Command: This command shows your recent command history. It’s useful for recalling and reusing previous commands.Scripting: Basic shell scripting can automate repetitive tasks. Learning to write simple scripts can save a lot of time.Stay Informed About Your System: Commands like top, htop, df, and free are great for monitoring system resources and performance.Practice Safe Command Practices: Always double-check commands, especially those that can modify or delete data (rm, mv, dd, etc.). A small typo can sometimes lead to big problems.Explore Interactive Shells: Tools like ipython for Python or interactive shells for other languages can be very useful for testing out commands and scripts.