Top Linux Command Line Tips Every User Should Know

Prerequisites

Basic understanding of Linux
Sudo or root privileges
The user should have a Linux operating system installed on their machine

Introduction

The Linux command line is a powerful tool that can significantly enhance your productivity and control over your system. Whether you're a beginner or an experienced user, mastering the command line can help you accomplish tasks faster, automate processes, and navigate your system with greater efficiency.

In this guide, we'll explore some of the top Linux command line tips that every user—regardless of experience—should know. From basic shortcuts to more advanced techniques, these tips will streamline your workflow, improve your command line skills, and make working with Linux a breeze. Whether you're managing files, running scripts, or troubleshooting, these essential tips will help you get the most out of your Linux experience.

Keyboard Shortcuts for Efficient Terminal Navigation

• Jump to the Beginning of the Line
  • ctrl + a
• Jump to the End of the Line
  • ctrl + e
• Clear the Line:
  • ctrl + u
• Interrupt the Current Command:
  • ctrl + c
• Autocomplete the Command or Filename
  • Tab
• Move to the Next Command
  • down arrow
• Move to the Previous Command
  • up arrow
• Search Command History
  • ctrl + r
    • Keep typing the search term, and it will cycle through previous commands that match.
• Jump Left One Word
  • esc + b
• Jump Right One Word
  • esc + f

Essential Linux Command Line Tips to Boost Your Productivity

Use !! to repeat last command

If you just executed a command and want to run it again, you can type:

!!

Use history to view command history

This will filter the command history for commands containing "search_term."

history | grep 'search_term'

• | (pipe): This is used to send the output of one command as input to another
• tail -n 10: This command limits the output to the last 10 lines, effectively showing only the last 10 commands in the history

history | tail -n 10

Use man to view command documentation

This will show you the manual for the ls command

man ls

List detailed information about all files in the current directory that end with .php

ls -l *.php

Use grep to search within files

grep 'search_term' filename

Summary of what grep -rnw . -e "pattern" does:

• -r: This option tells grep to search recursively through all subdirectories, starting from the specified directory (in this case, . which refers to the current directory).
• -n: This option causes grep to show the line number where the matching string is found within each file.
• -w: This option ensures grep matches the whole word. It means that grep will only match when it appears as a complete word, not as part of another word.
• -e: This option allows you to specify the pattern you are search for.

Use find to locate files

• find / -name "filename"
• find . -name "filename"
• To search for all .txt files
  • find / -name "*.txt"
• find . -name "*txt*"
  • searches the current directory and its subdirectories for any file or folder with "txt" in the name
• to find files that start with txt
  • find . -name "data*"
• to find files that end with txt
  • find . -name "*txt"

Exploring the Role of /, ., and * in Linux Filesystem Navigation and Commands

• The single / (without any other path) refers to the root directory, which is the top-most directory in the filesystem hierarchy. Every other file or directory on the system is located under this root directory.
• The . symbol specifies the current directory (and its subdirectories) as the starting point for the search.
• The asterisks (*) are wildcards, meaning they match any characters before or after txt. So, the command will find files or directories with names that include txt (e.g., file.txt, textfile.txt, documenttxt, somefile_txt, etc.).

Using tail to Monitor Real-Time Log Data: Analyzing Authentication Events and Login Attempts

For CentOS (RHEL-based systems)

To monitor login events in real-time:

sudo tail -n 5 -f /var/log/secure

For Ubuntu (Debian-based systems)

To monitor login events in real-time:

sudo tail -n 5 -f /var/log/auth.log

• -n <number_of_lines>: Specifies the number of lines you want to see from the end of the file. For example, -n 5 will show the last 5 lines.
• -f: Stands for "follow", which allows tail to keep updating and displaying new lines as they are added to the file.

Quick Navigation with cd ~, cd -, and cd

• cd ~: When you run cd ~, you are taken directly to your home directory, regardless of where you are in the file system.
• cd -: The cd - command switches to the previous directory you were in. It's useful for toggling between two directories.
• cd (without arguments): When you use cd without any arguments, it will take you to your home directory, just like cd ~

Use alias to Create Shortcuts for Commands

You can create shortcuts for long commands using alias. For example:

alias df="df -h -x tmpfs -x devtmpfs"

This creates an alias named df, so every time you type df in the terminal, it will run the full command df -h -x tmpfs -x devtmpfs instead.

This alias ensures that whenever you run the df command, it will show the disk usage in a human-readable format, excluding the memory-based file systems (tmpfs and devtmpfs) from the output.

Redirecting Output to Create or Clear a File with >

> myfile.txt

• If myfile.txt does not already exist, it will create an empty file named myfile.txt in your current directory.
• If myfile.txt already exists, it will clear the contents of the file, leaving it empty.

Creating Multiple Directories at Once with mkdir -p and Brace Expansion

mkdir -p new_folder/{folder_1,folder_2,folder_3}

The command mkdir -p new_folder/{folder_1,folder_2,folder_3} creates a directory structure with multiple folders inside a parent folder.

• mkdir: This command is used to create directories.
• -p: This option ensures that any parent directories needed in the path are created as well.
• new_folder/{folder_1,folder_2,folder_3}: This part uses brace expansion to create multiple directories at once.

Executing Multiple Commands Sequentially with &&

mkdir new_folder && cd new_folder && touch file.txt

The command executes multiple commands sequentially, but only if the previous command in the chain succeeds.

• &&: This is a logical AND operator in the shell. It is used to chain commands together, ensuring that each command runs only if the preceding command succeeds.

Final Thoughts

Mastering the Linux command line is a powerful way to enhance your productivity and take full control of your system. With the tips and tricks covered in this guide, you're now equipped with some of the most essential and time-saving commands to navigate your file system, manage processes, and optimize your workflow. Remember, the command line is vast, and these are just the beginning. The more you practice and explore, the more you'll unlock its potential. So, keep experimenting, stay curious, and don't hesitate to dive deeper into Linux's rich command-line ecosystem. Happy hacking!