Linux

cat and less — reading file contents from the terminal

Aftab Siddique

— 2 min read

Have you ever tried to quickly check a configuration file or debug a script, only to realize your desktop environment is sluggish, or worse, completely missing? That moment when you need to peek inside a text file but everything feels clunky is familiar to every new Linux user. Luckily, the terminal has two built-in utilities that solve this instantly: cat and less.

Why This Matters for Beginners

Learning these commands early changes how you interact with your system. First, servers and remote machines rarely come with a graphical interface. When you connect via SSH, your only window into the system is the command line. Second, opening files through a GUI can be frustratingly slow when dealing with large logs or dozens of config files. Mastering cat and less gives you instant access to file contents, speeds up your workflow, and builds the muscle memory needed for more advanced Linux tasks. Once you understand how these tools work together, navigating the terminal will feel less like typing into a void and more like holding a reliable flashlight in a dark room.

Step-by-Step Walkthrough

Follow these steps to get comfortable with both commands:

  • Step 1: Create a sample file to practice with. You will need some text to view before running any commands. Use the echo command to generate a quick test file named sample.txt:
echo "This is line one." > sample.txt
echo "This is line two." >> sample.txt
echo "This is line three." >> sample.txt
  • Step 2: View the entire file instantly using cat. The cat command (short for concatenate) dumps the full contents of a file directly into your terminal screen. It is perfect for short files. Run this command to see what is inside your test file:
    cat sample.txt
  • Step 3: Switch to less for longer or unpredictable files. When a file has hundreds of lines, cat will scroll past everything too fast. The less command opens the file in a dedicated viewer that waits for your input. Open your file like this:
    less sample.txt
  • Step 4: Navigate through pages and search inside less. Once less is open, you control the movement. Use the arrow keys or Page Up/Page Down to scroll line by line or page by page. Press q to quit and return to your prompt whenever you are done. If you need to find a specific word, press /, type your search term, and hit Enter:
/line two
n  (to jump to the next match)
q  (to exit less)
  • Step 5: Pipe output into less for better control. You do not have to open files directly. You can also send the output of any command straight into less using a pipe symbol. This is incredibly useful when checking system information or logs:
    ls -la | less

Common Beginner Mistakes to Avoid

Keep this checklist in mind while practicing to save yourself time and frustration:

  • Do not use cat on massive log files or system directories, as it will flood your terminal and make it difficult to read anything.
  • Always remember that pressing q is the only reliable way to exit less; hitting Ctrl+C will interrupt the command rather than close it cleanly.
  • Double-check your file paths before running commands, since cat and less will silently fail if you misspell a filename or use the wrong directory.
  • Never run these tools with elevated privileges unless absolutely necessary, as accidental edits or misread permissions can cause system issues.

Learning to read files from the terminal might feel unfamiliar at first, but practicing these two commands daily will quickly turn them into your go-to tools for quick inspections and efficient troubleshooting. Whenever you need hands-on guidance to build confidence with Linux fundamentals, Solv-IT is here to help you succeed.

Read more