Bandit Level 11-12
tr (short for translate) command can be used to delete and modify data according to a pattern.
An example:
cat data.txt | tr [:lower:] [:upper:]
This command would change all of the lowercase letters into the uppercase letters that it recieved from the data.txt file and output them.
In this case, we want to use the ROT13 cypther. Thus, we have to move 13 places to the right.
To do so, we have to use REGEX (regular expression).
Please, try to read more about the problem and see if you can figure it out before checking my solution.
cat "once again, plese try."
cat "i insist" | | tr [:lower:] [:upper:]
cat data.txt | tr 'A-Za-z' 'N-ZA-Mn-za-m'
output: The password is ---flag---