50 Linux Commands everyone should know about
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The world of web development is constantly evolving. To succeed, having a solid understanding of Linux commands is a must. Linux, an open-source operating system, powers the majority of web servers worldwide, making it a crucial skill for anyone working in the web development field. According to a report, there are?32.8 million?Linux users in the world, in addition to 1.6 billion Android users.
Linux is also a popular choice for?hosting VPS (Virtual Private Server)?environments due to its stability, flexibility, security, and cost-effectiveness.
Whether you’re a seasoned professional or just starting your coding journey, familiarizing yourself with basic Linux commands is an essential step towards mastering the command-line interface
In this article, we will explore a selection of fundamental Linux commands that every developer should know.
What is a Linux Command?
A Linux command is a textual instruction that you can enter into a Linux shell or terminal to perform various tasks and operations on a Linux operating system.
As a web developer, your interaction with a Linux environment will primarily occur through the command-line interface (CLI). While graphical user interfaces (GUIs) exist, the CLI offers unparalleled control and efficiency when working on remote servers or managing complex systems
By gaining proficiency in Linux commands, you’ll be able to navigate the file system, manipulate files and directories, install software, configure servers, automate tasks
In the following sections, we will explore a curated list of fundamental Linux commands that will empower you to work with confidence in a Linux-based web development environment. Let’s get started.
List of Linux Commands
1. ls Command
Purpose:?List files and directories from the CLI
It is similar to navigating in the File Explorer with a GUI.
The ls – l displays detailed information about files and directories in the current directory. If you want to check files in another directory, you can type the?ls {directory path}?command. You can further interact with these directories using different commands.
2. cd
Purpose: Change the directory.
This command helps you change the current working directory. By default, the terminal will open the home directory.
To go to a separate path, you can type cd /path/to/directory to navigate to a specified directory.
The command also supports various arguments like:
cd / = will take you to the root directory
cd – = to go to a previous directory
cd /folder/subfolder = for custom navigation
3. pwd
Purpose:?Display the path name of the working directory.
The command pwd (Print?Working?Directory) prints the path of the working directory.
It is a shell built-in command.
pwd -L will print the symbolic path
pwd -P will print the actual path
4. mkdir
Purpose:?Create a new directory.
The command mkdir helps you create directories. It is somewhat similar to creating folders in other operating systems.
It can create multiple directories along with the permission parameters.
The user needs to have permission to create a directory in the parent directory. In lack of permissions, the user might get the permission denied error.
Example: mkdir fresh_directory creates a directory named “fresh_directory”.
5. rm
Purpose: Remove files and directories.
To eliminate unnecessary files, you can utilize the “rm” command. This command effectively eradicates specified files, a group of files, or specific files from a directory’s listing. Unlike other operations, such as user confirmation, read permission, or write permission, the removal process with the “rm” command does not necessitate these prerequisites.
Example: rm myfile deletes a file named “myfile”.
6. cp
Purpose:?Copy files and directories.
cp is short for copy. Using this command, users can copy files or groups of files and directories. This command creates an exact copy of the file and names it differently.
The syntax for this command requires at least two arguments. It will copy the first file’s content to the second file. If the second file is not present, it will first create one and then copy the content. But if it exists, the content is overwritten without any warning. One should use this command carefully.
Example: cp a.txt b.txt
7. mv
Purpose:?Move or rename files and directories.
mv is short for move. This command is used for renaming file directories and moving files from one location to another.
This command can help you manage directories and files in any Linux-based system.
Example: mv fresh.txt new_location/ moves “fresh.txt” to the “new_location” directory.
8. touch
Purpose:?Create an empty file or update the timestamp of an existing file
The “touch” command in Linux is used to create an empty file or update the timestamp of an existing file. It is a simple and versatile command that allows users to modify file timestamps or create new files without any content.
Example: touch file.txt command will create a new empty file named “file.txt”.
9. cat
Purpose:?Concatenates and displays the contents of files.
The “cat” command in Linux is used to display the contents of a file on the terminal. It is also commonly used to concatenate and combine multiple files into a single file. It is a versatile command that provides a quick and straightforward way to view and manipulate file contents.
Example: cat file.txt will display the contents of “file.txt” in the terminal.
10. less
Purpose:?View file contents interactively.
The “less” command in Linux is a pager program that allows users to view and navigate through the contents of a file.
It is particularly useful for viewing large files, as it allows scrolling both forward and backward, searching for specific text, and provides a more interactive and user-friendly experience compared to the “cat” command.
Example: less file.txt allows you to scroll through the contents of “file.txt” using arrow keys.
11. grep
Purpose:?Search for specific patterns within files.
The “grep” command in Linux is used to search for specific patterns or text within files. The grep is short for the global regular expression print.
It scans one or multiple files and prints the lines containing the matching pattern. It is a powerful command that allows for pattern-based searching, making it a handy tool for filtering and extracting information from files.
Example: grep “search_term” file.txt searches for “search_term” within “file.txt” and displays matching lines.
12. find
Purpose:?Search for various files and directories based on a given criteria.
The “find” command in Linux is used to search for files and directories based on various criteria such as name, size, type, and modification time. It traverses a directory hierarchy starting from a specified location and returns a list of files and directories that meet the specified conditions. It is a versatile command for locating files and performing operations on them.
Example: find /path/to/search -name “filename” searches for files with the specified name in the given directory.
13. chmod
Purpose:?Change file access permissions.
chmod is short for change mode. It can help you change the permissions of the files and directories. It allows users to modify the access rights for owners, groups, and others, granting or revoking permissions to read, write, and execute files. It provides fine-grained control over file permissions, ensuring appropriate levels of security and access control.
Example: chmod 755 file.txt sets the file permissions of “file.txt” to read, write, and execute for the owner, and read and execute for others.
14. chown
Purpose:?Change file ownership
The “chown” command in Linux helps you change the ownership of files and directories. It allows users to transfer ownership of a file or directory to a different user or group. This command is particularly useful for managing file permissions and ensuring that the appropriate users have control over specific files and directories.
Example: chown owner_name file_name changes the owner of the file to the specified user.
15. chgrp
Purpose:?Change group ownership of files
The “chgrp” command in Linux is used to change the group ownership of files and directories. It allows users to assign different group ownership to a file or directory, granting access and permissions to members of that group. This command is helpful for managing file permissions and ensuring proper group-level access control.
Example: chgrp group file.txt changes the group ownership of “file.txt” to the specified group.
16. tar
Purpose:?Archive and extract files.
The “tar” command in Linux is used to create, extract, and manage archived files in the TAR format. It combines multiple files and directories into a single archive file, which can be compressed with other tools like gzip or bzip2. The “tar” command is commonly used for bundling files, creating backups, and transferring directories while preserving their structure and permissions.
Example: tar -cvf archive.tar file.txt creates a new archive file “archive.tar” containing “file.txt”.
17. gzip
Purpose:?Compress files using the gzip algorithm.
The “gzip” command in Linux is used to compress files and reduce their size. It creates a compressed version of the specified file, replacing the original file with a compressed version ending in “.gz”. The “gzip” command is widely used to save disk space, reduce file transfer time, and work with compressed files efficiently.
Example: gzip file.txt compresses “file.txt” and renames it as “file.txt.gz”.
18. gunzip
Purpose:?Decompress files compressed with gzip.
The “gunzip” command in Linux is used to decompress files that have been compressed with gzip. It takes a file with the “.gz” extension and restores it to its original, uncompressed form. The “gunzip” command is commonly used to extract files from compressed archives or when working with gzip-compressed files. It also supports other extensions like.gz, .z, _z, -gz, -z , .Z, .taz or.tgz.
Example: gunzip file.txt.gz decompresses “file.txt.gz” and restores it as “file.txt”.
19. ssh
Purpose:?Securely connect to remote servers.
The “ssh” command in Linux is used to establish a secure, encrypted connection to a remote server or device over a network. It allows users to remotely access and control systems, transfer files, and execute commands on the remote machine securely. The “ssh” command is widely used for secure remote administration
Example: ssh?username@remote_host establishes an SSH connection to the specified remote host.
20. scp
Purpose:?Securely copy files between local and remote systems.
The “scp” command in Linux is used for securely copying files between a local and remote machine or between two remote machines. It uses the SSH protocol to establish an encrypted connection and securely transfer files. The “scp” command is efficient for transferring files, directories, or even entire file systems securely across different systems.
Example: scp file.txt?username@remote_host:/path/to/destination copies “file.txt” from the local system to the specified destination on the remote host.
21. wget
Purpose: Download files from the web.
The wget command in Linux is used to retrieve files from the web using the HTTP, HTTPS, and FTP protocols. It allows you to download files non-interactively, making it useful for automated tasks or downloading large batches of files.
Example: wget https://example.com/file.txt downloads “file.txt” from the specified URL.
22. curl
Purpose: Transfer data to or from a server using various protocols.
The curl command in Linux is a versatile tool used to transfer data to or from a server, supporting various protocols like HTTP, HTTPS, FTP, and more. It can perform requests, handle cookies, and supports features like authentication, proxy connections, and file uploads, making it a powerful tool for interacting with web services.
Example: curl https://example.com retrieves the content of a web page from the specified URL.
23. top
Purpose:?Monitor system processes and resource usage.
The top command in Linux provides real-time monitoring of system processes. It displays a dynamic, interactive view of the most resource-intensive processes, including CPU usage, memory utilization, and other system statistics. It helps users identify performance bottlenecks and manage system resources efficiently.
Example: top displays a dynamic view of running processes, CPU usage, and memory statistics.
24. ps
Purpose:?Display running processes.
The ps command in Linux is used to provide information about running processes on the system. It displays a snapshot of the currently running processes, including their process IDs (PIDs), resource utilization, and relationships between processes. It helps users monitor and manage processes, identify problematic ones, and perform various process-related operations.
Example: ps aux shows a list of all running processes with detailed information.
25. kill
Purpose:?Terminate processes by ID or name.
The kill command in Linux is used to terminate or send specific signals to running processes. By specifying the process ID (PID) or process name, it allows users to gracefully stop processes or forcefully terminate them. It is commonly used for process management and troubleshooting purposes in order to stop misbehaving or unresponsive programs.
Example: kill 1234 terminates the process with the specified process ID.
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26. df
Purpose:?Show disk space usage.
The df command in Linux is used to display information about the available disk space on file systems. It provides details such as total disk space, used space, available space, and file system types for mounted partitions. This command helps users monitor disk usage, identify storage capacity, and manage file systems efficiently.
Example: df -h displays disk space usage in a human-readable format.
27. du
Purpose: Estimate file and directory sizes.
The du command in Linux is used to estimate disk usage for files and directories. It provides information on the sizes of individual files and directories, as well as the total size of a directory and its subdirectories. It helps users identify space-consuming files and directories, allowing them to manage disk usage and optimize storage efficiency.
Example: du -sh directory provides a summary of the total disk usage of the specified directory.
28. head
Purpose:?Display the first lines of a file.
The head command in Linux is used to display the beginning or the first few lines of a file. By default, it shows the first 10 lines, but this can be customized. It is helpful for quickly previewing the contents of a file or extracting the initial portion of a large file.
Example: head -n 10 file.txt shows the first 10 lines of “file.txt”.
29. tail
Purpose:?Display the last lines of a file.
The tail command in Linux is used to display the end or the last few lines of a file. By default, it shows the last 10 lines, but this can be adjusted. It is useful for monitoring log files in real-time or extracting the recent entries from a file.
Example: tail -n 5 file.txt shows the last 5 lines of “file.txt”.
30. ln
Purpose:?Create links between files.
The ln command in Linux is used to create links between files. It can create hard links or symbolic links (also known as soft links). Hard links are direct references to the same physical file, while symbolic links are pointers to the file’s location. The ln command helps establish file associations and provides flexibility in organizing and accessing files within the file system.
Example: ln -s source.txt link.txt creates a symbolic link “link.txt” pointing to “source.txt”.
31. tac
Purpose:?Displays file content in reverse order.
The tac command in Linux is used to reverse the order of lines in a file. It reads the contents of a file and prints them out in reverse order. The tac command is often considered the opposite of the cat command. While cat displays the contents of a file in the order they appear, tac reverses the order and displays the contents in reverse. So, in a way, you can think of tac as the reverse of cat.
Example: Tac file.txt displays content from the file name file.txt in reverse order
32. sed
Purpose:?Stream editor for text manipulation.
The sed command in Linux, short for “stream editor,” is used for text manipulation and transformation. It reads text from standard input or files, applies specified operations or commands, and then outputs the modified text. sed is commonly used for tasks like search and replace, text substitutions, line editing, and more, making it a versatile tool for automating text processing tasks.
Example: sed ‘s/old/new/’ file.txt replaces the first occurrence of “old” with “new” in “file.txt”.
33. awk
Purpose:?Text processing and pattern matching tool.
The awk command in Linux is a powerful text-processing tool that operates on fields and records in a file or input stream. It allows for data extraction, manipulation, and reporting based on specified patterns and actions. awk is particularly useful for parsing structured data and generating formatted reports, making it a versatile tool for data analysis and processing in the command line.
Example: awk ‘{print $1}’ file.txt prints the first field of each line in “file.txt”.
34. cut
Purpose:?Extract sections from lines of files.
The cut command in Linux is used to extract specific sections or columns from lines of text or files. It allows users to define a delimiter and select certain fields based on character positions or column numbers. cut is helpful for data extraction, splitting fields, and processing structured data, enabling users to extract and work with specific parts of text or file content.
Example: cut -d ‘,’ -f 1 file.csv extracts the first field of each line in a CSV file using comma as the delimiter.
35. sort
Purpose:?Sort lines in a file.
The sort command in Linux is used to sort the lines of text or files in either ascending or descending order. It arranges the lines alphabetically or numerically based on the specified criteria. sort is useful for organizing data, finding duplicates, and preparing files for further processing or analysis, making it an essential tool for data manipulation and organization.
Example: sort file.txt sorts the lines in “file.txt” in ascending order.
36. uniq
Purpose:?Remove duplicate lines from a file.
The uniq command in Linux is used to filter and display unique lines from a sorted input file or from the output of another command. It compares adjacent lines and removes duplicates, leaving only one occurrence of each unique line. This command is commonly used to identify and eliminate duplicate entries from text files or to extract unique records from datasets.
Example: uniq file.txt removes consecutive duplicate lines from “file.txt”.
37. diff
Purpose:?Compare files line by line
The diff command in Linux is used to compare and highlight the differences between two text files or directories. It shows the line-by-line variations between the files, indicating additions, deletions, and modifications. This command is helpful for identifying discrepancies and tracking changes between versions of files or directories.
Example: diff file1.txt file2.txt displays the differences between “file1.txt” and “file2.txt” line by line.
38. man
Purpose:?Display the manual pages for commands.
The man command in Linux is used to display the manual pages for various commands, system functions, and configuration files. It provides detailed documentation, explanations, and usage examples for a wide range of topics. man is a valuable tool for accessing comprehensive information and learning about the available features and functionalities in Linux.
Example: man ls shows the manual page for the “ls” command, providing detailed information and usage instructions.
39. history
Purpose:?Show command history.
The history command in Linux displays a list of previously executed commands from the user’s command-line session. It provides a chronological record of commands along with their line numbers, which can be recalled and executed again. history is useful for reviewing past commands, repeating or modifying them, and quickly accessing frequently used commands.
Example: history lists the previously executed commands in the current session.
40. alias
Purpose:?Create shortcuts for frequently used commands.
The alias command in Linux allows users to create and manage custom shortcuts or aliases for commands or command sequences. It enables users to define shorter or more convenient names for frequently used commands or complex command combinations. alias improves command-line productivity by reducing typing and providing a more intuitive and personalized command experience.
Example: alias ll=’ls -l’ creates an alias “ll” for the “ls -l” command, allowing you to use “ll” instead.
41. su
Purpose:?Switch to another user account.
The su command in Linux is used to switch to another user account or become a superuser (root). It prompts for the password of the target user and opens a new shell session with the privileges of that user. su is often used to perform administrative tasks or run commands that require elevated permissions on a Linux system.
Example: su username switches to the specified user account.
42. sudo
Purpose:?Execute commands with administrative privileges.
The sudo command in Linux allows users to execute commands with elevated privileges, typically as the superuser (root). It requires the user to authenticate with their own password and provides a more secure way to perform administrative tasks. sudo is widely used to execute privileged commands while maintaining fine-grained control over user access and permissions.
Example: sudo apt-get update updates the package repositories using administrative privileges.
43. apt-get
Purpose:?Package manager for Debian-based systems.
The apt-get command in Linux is used for package management in Debian-based systems. It enables users to install, upgrade, or remove software packages from repositories. apt-get automatically resolves dependencies and ensures a smooth installation process, making it a convenient and widely used tool for managing software packages in Linux.
Example: apt-get install package_name installs a package using the APT package manager.
44. yum
Purpose:?Package manager for RPM-based systems.
The yum command in Linux is used for package management in RPM-based systems, such as Red Hat Enterprise Linux (RHEL) and CentOS. It allows users to install, upgrade, or remove software packages from repositories. yum handles package dependencies and provides a reliable method for managing software packages in Linux distributions that use the RPM package format.
Example: yum install package_name installs a package using the YUM package manager.
45. systemctl
Purpose:?Control system services.
The systemctl command in Linux is used for controlling and managing systemd services and units. It enables users to start, stop, restart, enable, disable, and query the status of services. systemctl provides a centralized and standardized approach to managing system services, making it a fundamental tool for service management in modern Linux distributions.
Example: systemctl start service_name starts a system service specified by “service_name”.
46. ifconfig
Purpose:?Configure network interfaces.
The ifconfig command in Linux is used to configure and display network interface information. It allows users to view and modify network interface settings such as IP addresses, netmasks, and network-related parameters. ifconfig is commonly used for network troubleshooting, configuring network interfaces, and obtaining network information in Linux systems.
Example: ifconfig eth0 displays the configuration details of the “eth0” network interface.
47. ping
Purpose:?Test network connectivity.
The ping command in Linux is used to test network connectivity by sending ICMP echo requests to a specified IP address or hostname. It measures the round-trip time for packets to reach the target and return. ping is a commonly used tool for network troubleshooting, checking network reachability, and diagnosing network latency or packet loss issues.
Example: ping example.com sends ICMP echo requests to “example.com” to check network connectivity.
48. traceroute
Purpose:?Determine the route packets take to reach a destination.
The traceroute command in Linux is used to trace the route taken by packets from a source to a destination host. It provides a list of intermediate routers or hops along with their response times. traceroute helps in diagnosing network connectivity issues, identifying network bottlenecks, and determining the path packets take through the network.
Example: traceroute example.com traces the network route from your system to “example.com”.
49. netstat
Purpose:?Network statistics and connection monitoring.
The netstat command in Linux is used to display network statistics and information. It provides details about active network connections, listening ports, routing tables, and other network-related data. netstat is useful for monitoring network activity, troubleshooting network issues
Example: netstat -an displays all active network connections and listening ports.
50. ssh-keygen
Purpose:?Generate SSH key pairs for secure authentication.
The ssh-keygen command in Linux is used to generate SSH key pairs for secure authentication. It creates public and private keys that can be used to establish secure connections between systems. ssh-keygen is commonly used for setting up secure remote access, enabling passwordless logins, and enhancing the security of SSH connections in Linux environments.
Example: ssh-keygen -t rsa generates an RSA key pair for SSH authentication.
Tips for using Linux Commands
Here are a few tips to help you make the most out of your command-line experience:
1. Practice and Experiment: The best way to become proficient in using Linux commands is through practice. Set aside dedicated time to explore and experiment with different commands, options, and combinations. The more you practice, the more comfortable and confident you will become.
2. Utilize Command-Line Help: Linux provides extensive documentation for each command through manual pages. Access them by typing man command_name. The manual pages offer detailed information about the command’s usage, options, and examples. Use man to explore commands and learn their capabilities.
3. Use Tab Completion:?Take advantage of tab completion by pressing the Tab key while typing commands, file names, or paths. It saves time and ensures accuracy, especially for long and complex file or directory names.
4. Redirect and Pipe Output:?Linux commands offer powerful output manipulation capabilities. Use redirection (>, >>) to redirect command output to a file or pipe (|) to pass the output of one command as input to another. This allows for advanced data processing and analysis.
5. Create Aliases:?Save time and simplify command usage by creating aliases for frequently used commands or command combinations. For example, you can set up an alias like alias ll=’ls -l’ to use ll instead of ls -l for listing files in a detailed format.
6. Regularly Update and Secure Your System: Keep your Linux system up to date with the latest security patches and updates. Use the package manager (apt-get, yum, etc.) to regularly update installed software packages and maintain a secure environment.
By implementing these tips, you’ll gradually become more proficient and efficient in using Linux commands, enabling you to streamline your web development workflow.
We hope the top Linux commands we discussed in this article will help you equip yourself with the foundational knowledge needed to navigate the command line, manage files and directories, manipulate data, and interact with remote servers.
Linux Commands FAQs
Q1: Can I use Linux commands on other operating systems?
A: While Linux commands are primarily designed for Linux-based systems, many commands have equivalents or a similar functionality on other operating systems like macOS and Unix.
Q2: What should I do if I encounter a “Permission denied” error when running a command?
A: Ensure that you have the necessary permissions to execute the command. If needed, use the sudo command to run commands with administrative privileges.
Q3: How can I find specific command options or usage examples?
A: Use the man command followed by the desired command name to access the manual pages, which provide detailed information and usage examples.
Q4: Can I undo a command that I mistakenly executed?
A: Some commands, like rm, have irreversible consequences. It’s essential to double-check before executing such commands. Consider creating backups or using version control systems for critical files.
Q5: How can I stay updated with new Linux commands and techniques?
A: Stay connected with the Linux and web development communities. Follow blogs, forums, and social media channels to stay updated.