The command line is an indispensable tool for developers working on Linux-based systems. It provides a powerful and efficient way to interact with the operating system, perform various tasks, and manage the development environment.
If you are a developer, mastering the command line can significantly boost your productivity and make your life much easier.
In this article, we will explore some of the most fundamental and useful Linux commands that you cannot afford to ignore as a developer. From basic navigation to advanced system operations, these commands will equip you with the necessary skills to work proficiently in a Linux environment.
| Category | Command | Description | Usage Example |
|---|---|---|---|
| Basic Navigation | ls | List files and directories | ls |
| cd | Change directories | cd /path/to/directory | |
| pwd | Present working directory | pwd | |
| mkdir | Create directories | mkdir new_directory | |
| rmdir | Remove empty directories | rmdir empty_directory | |
| File Operations | touch | Create files | touch new_file.txt |
| cp | Copy files and directories | cp file.txt /path/to/destination/ | |
| mv | Move or rename files and directories | mv file.txt /path/to/destination/ | |
| rm | Remove files and directories | rm file.txt | |
| cat | Display file content | cat file.txt | |
| more / less | View file content page by page | less large_file.txt | |
| Text Processing | grep | Search for patterns in files | grep 'keyword' file.txt |
| sed | Stream editor for text manipulation | echo 'Hello World!'| sed 's/Hello/Hi/' | |
| awk | Text processing and data extraction | awk '{print $1}' data.txt | |
| System Information | top | Monitor system processes | top |
| free | Check memory usage | free -h | |
| df / du | Display disk space information | df -h | du -h | |
| uname | Show system information | uname -a | |
| ps | Display process status | ps aux | |
| Package Management | apt / apt-get | Debian-based package management | sudo apt update | sudo apt install package_name |
| yum | Red Hat-based package management | sudo yum update | sudo yum install package_name | |
| dnf | Next-generation package manager | sudo dnf update | sudo dnf install package_name | |
| pacman | Arch Linux package management | sudo pacman -Syu | sudo pacman -S package_name | |
| Networking | ping | Check network connectivity | ping google.com |
| ifconfig / ip | Configure network interfaces | ifconfig | |
| ssh | Securely access remote machines | ssh user@remote_host | |
| scp | Copy files between local and remote systems | scp file.txt user@remote_host:/path/to/destination/ | |
| curl / wget | Download files from the web | curl -O https://example.com/file.txt | |
| File Permissions | chmod | Change file permissions | chmod +x script.sh |
| chown | Change file ownership | chown user file.txt | |
| chgrp | Change group ownership | chgrp group file.txt | |
| Compression and Archiving | tar | Create and extract tarballs | tar -cvf archive.tar file1 file2 |
| gzip / gunzip | Compress and decompress files | gzip file.txt | gunzip file.txt.gz | |
| Process Management | kill / killall | Terminate processes | kill process_id | killall process_name |
| bg / fg | Manage background and foreground processes | bg | fg | |
| Environment Variables | export | Set environment variables | export VARIABLE_NAME=value |
| echo | Display the value of variables | echo $VARIABLE_NAME | |
| Command History | history | View command history | history |
| Ctrl+R | Search command history | (Press Ctrl+R and type search query) | |
| Useful Utilities | date | Display or set the system date and time | date |
| cal | Display a calendar | cal | |
| bc | Command-line calculator | echo '2+2' | bc |
Basic Navigation Commands
1. ls : Listing Files and Directories
The ls command is used to list the files and directories in the current working directory. By default, it displays the names of the files and directories in a straightforward format.
$ ls
file1.txt file2.txt directory1 directory2
You can also use various options with
ls to get more information, such as file sizes, permissions, and timestamps. 2. cd : Changing Directories
The cd command is used to change directories. It allows you to navigate through the file system and access different directories.
$ cd /path/to/directory
3. pwd : Present Working Directory
The
pwd command displays the absolute path of the current working directory.
$ pwd
/path/to/directory
4. mkdir : Creating Directories
The mkdir command creates a new directory with the specified name.
$ mkdir new_directory
5. rmdir : Removing Directories
The `rmdir` command is used to remove empty directories.
$ rmdir empty_directory
File Operations
6. touch : Creating Files
The touch command creates a new empty file with the specified name.
$ touch new_file.txt
7. cp : Copying Files and Directories
The cp command is used to copy files or directories from one location to another.
$ cp file.txt /path/to/destination/
8. mv : Moving or Renaming Files and Directories
The mv command moves files or directories from one location to another. It can also be used to rename files or directories.
$ mv file.txt /path/to/destination/
$ mv old_name.txt new_name.txt
9. rm : Removing Files and Directorie
The rm command is used to remove files or directories. Use it with caution, as the data deleted by this command cannot be easily recovered.
$ rm file.txt
$ rm -r directory/
10. cat : Displaying File Content
The `cat` command is used to display the contents of a file.
$ cat file.txt
11. more and less : Viewing File Content Page by Page
The `more` and `less` commands allow you to view file content page by page, which is useful for large files.
$ more large_file.txt
$ less large_file.txt
Text Processing
12. grep : Searching for Patterns in Files
The `grep` command is used to search for a specific pattern or text in a file.
$ grep "keyword" file.txt
13. sed : Stream Editor for Text Manipulation
The `sed` command is a powerful stream editor that allows you to perform text manipulation based on regular expressions.
$ echo "Hello, World!" | sed 's/Hello/Hi/'
14. awk : Text Processing and Data Extraction
The `awk` command is a versatile tool for text processing and data extraction. It processes text line by line and allows you to perform actions on specific columns.
$ awk '{print $1}' data.txt
System Information
15. top : Monitoring System Processes
The `top` command provides real-time monitoring of system processes and resource usage.
$ top
16. free : Checking Memory Usage
The `free` command displays the system’s free and used memory.
$ free -h
17. df and du: Displaying Disk Space Information
The `df` command shows the disk space usage of file systems, while `du` shows the disk usage of directories.
$ df -h
$ du -h
18. uname : Showing System Information
The `uname` command displays system information, such as the kernel version and system architecture.
$ uname -a
19. ps : Displaying Process Status
The `ps` command provides information about currently running processes.
$ ps aux
Package Management
20. apt and apt-get: Package Management on Debian-based Systems
`apt` and `apt-get` are package management tools used on Debian-based systems like Ubuntu.
$ sudo apt update
$ sudo apt install package_name
21. yum : Package Management on Red Hat-based Systems
The `yum` command is used for package management on Red Hat-based systems like CentOS.
$ sudo yum update
$ sudo yum install package_name
22. dnf: The Next-Generation Package Manager
`dnf` is a modern package manager used on newer versions of Fedora and CentOS.
$ sudo dnf update
$ sudo dnf install package_name
23. pacman : Package Management on Arch Linux
`pacman` is the package manager used on Arch Linux and its derivatives.
$ sudo pacman -Syu
$ sudo pacman -S package_name
Networking
24. ping : Checking Network Connectivity
The `ping` command is used to check network connectivity to a specific host.
$ ping google.com
25. ifconfig and ip : Configuring Network Interfaces
`ifconfig` and `ip` commands are used to configure network interfaces on Linux systems.
$ ifconfig
$ ip address show
26. ssh : Securely Accessing Remote Machines
The `ssh` command allows you to securely access remote machines over a network.
$ ssh user@remote_host
27. scp : Copying Files Between Local and Remote Systems
The `scp` command is used to securely copy files between local and remote systems.
$ scp file.txt user@remote_host:/path/to/destination/
28. curl and wget: Downloading Files from the Web
Both `curl` and `wget` commands can be used to download files from the internet.\.
$ curl -O https://example.com/file.txt
$ wget https://example.com/file.txt
File Permissions
29. chmod : Changing File Permissions
The `chmod` command is used to change file permissions, which control read, write, and execute rights.
$ chmod +x script.sh
30. chown : Modifying File Ownership
The `chown` command allows you to change the owner of a file.
$ chown user file.txt
31. chgrp : Changing Group Ownership
The `chgrp` command is used to change the group ownership of a file.
$ chgrp group file.txt
Compression and Archiving
32. tar: Creating and Extracting Tarballs
The `tar` command is used to create and extract tarballs, which are archive files.
$ tar -cvf archive.tar file1 file2
$ tar -xvf archive.tar
33. gzip and gunzip : Compressing and Decompressing Files
`gzip` and `gunzip` are used to compress and decompress files.
$ gzip file.txt
$ gunzip file.txt.gz
Process Management
34. kill and killall : Terminating Processes
The `kill` command is used to terminate processes by sending signals to them.
$ kill process_id
$ killall process_name
35. bg and fg : Managing Background and Foreground Processes
The `bg` and `fg` commands allow you to manage background and foreground processes.
$ bg
$ fg
Environment Variables
Environment variables are dynamic values that affect the behavior of processes in the shell.
37. Understanding Environment Variables
The `export` command is used to set environment variables.
$ export VARIABLE_NAME=value
38. echo : Displaying the Value of Variables
The `echo` command displays the value of environment variables.
$ echo $VARIABLE_NAME
Command History
39. history : Viewing Command History
The command history allows you to recall and reuse previously executed commands.
The `history` command displays a list of previously executed commands.
$ history
40. Ctrl+R: Searching Command History
Pressing `Ctrl+R` allows you to search for a command in the command history.
Useful Utilities
41. date : Displaying or Setting the System Date and Time
The `date` command displays or sets the system date and time.
$ date
$ sudo date MMDDhhmmYYYY
42. cal : Displaying a Calendar
The `cal` command displays a calendar for the current month.
$ cal
43. bc : Command-Line Calculator
The `bc` command is a command-line calculator for performing mathematical calculations.
$ echo "2+2" | bc
Conclusion
Congratulations! You have now explored a wide range of essential Linux commands that every developer should know. These commands will help you navigate the command line with ease, manage files and processes, and interact efficiently with your Linux-based development environment.
As you continue to work with the command line, you’ll discover even more commands and tricks that will enhance your productivity and effectiveness as a developer.
Remember to practice regularly and experiment with different commands to gain a deeper understanding of their capabilities. The command line might seem intimidating at first, but with time and practice, it will become an invaluable tool in your development toolkit.
Go Further!
FAQs
The command line is a text-based interface in the terminal where users can interact with the operating system by typing commands.
The command line provides developers with direct access to the underlying system, making it efficient for performing various tasks and automating processes.
You can navigate directories using commands like cd (change directory) to move to a specific directory, ls to list files and directories in the current location, and pwd to display the present working directory.
To create a new directory, use the mkdir command followed by the desired directory name. For example: mkdir new_folder.
You can use the cp command to copy files, mv to move or rename files. For example: cp file.txt destination/ or mv file.txt new_name.txt.
The grep command is used to search for text patterns in files. For instance: grep ‘search_text’ file.txt.
You can use the cat command to display the entire content of a file or less command to view it page-by-page. For example: cat file.txt or less file.txt.
Linux distributions often have package managers like apt, yum, or dnf. Use commands like sudo apt-get install package_name (for Debian-based systems) or sudo yum install package_name (for Red Hat-based systems) to install packages.
You can use the top command to display real-time information about system resources, including CPU, memory, and processes.
To compress files, use commands like tar (for creating tar archives) and gzip (for compression). For example: tar -czvf archive.tar.gz folder/. To decompress, use tar -xzvf archive.tar.gz.
The shutdown command allows you to initiate system shutdown or restart. Use sudo shutdown -h now to shut down immediately or sudo reboot to restart the system.
