Bandit 11 → 12
OverTheWire 
Linux Progressive Goal: decode a file where every letter has been rotated 13 places through the alphabet.
Approach
Section titled “Approach”bandit11@bandit:~$ cat data.txt | tr '[a-zA-Z]' '[n-za-mN-ZA-M]'The password you are looking for is: <password>Password
7x16WNeHIi5YkIhWsfFIqoognUTyj9Q4Why it works
Section titled “Why it works”ROT13 is a fixed Caesar shift of 13 over the 26-letter alphabet. Because 13 is half of 26, applying the same letter-for-letter tr mapping a second time shifts back to the original. It is reversible by design and protects nothing.