Shell01 42 [TRUSTED – PICK]

But once you finish it, you will never look at a terminal the same way again. You will start piping grep into awk into sort in your sleep. And that is exactly the point.

Here is what you need to know to survive (and thrive) in Shell01. Unlike traditional scripting exercises, 42’s Shell01 forbids the use of loops ( for , while , etc.) in several key exercises. Why? Because the Unix philosophy states that text manipulation should be done via filters .

The official goal of Shell01 is simple: "Introduction to basic commands and the manipulation of files and directories." However, anyone who has passed through 42’s common core knows the reality: shell01 42

find . -type f -name "*.sh" -exec basename {} .sh \; Key lesson: Read the find man page until you understand -exec and {} \; . Prompt: Count all files and directories in the current directory and all subdirectories.

Writing a manual counter with awk . Elegant Solution: sed -n 'p;n' (print, then skip next line). Key lesson: Learn sed 's addressing modes. One-liners beat multi-liners. 4. r_dwssap - The Mirror of /etc/passwd Prompt: Take /etc/passwd , keep every other line starting from the 2nd, reverse login order, swap : for spaces, and print only users with a specific shell. But once you finish it, you will never

Good luck, cadet. The shell awaits.

Many beginners try basename or complex string manipulation. Solution: Use find , sed , or basename with parameter expansion. Here is what you need to know to

If you have just finished Shell00 (where you learned to create files, manage permissions, and use ls ), Shell01 will feel like a sudden leap from "using a computer" to "thinking like a developer."