Introduction
If 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 and straightforward.
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!
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 Commands
Let’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 Commands
Now 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 Commands
Here 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 Commands
Linux 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.