Falaj 7: Only Once

Duplicate lines are easy to count and easy to overlook. This file is a log where almost everything is written more than once: the clerk copies every reading, so the repeats are noise. One line appears exactly once, and that line carries the password for the next level.

You could scroll through it, but the shell offers a better way. sort puts identical lines next to each other, and uniq -c collapses runs of identical lines and puts a count in front of each. Put the two together with a pipe and read the counts. The line whose count is one is the odd one out.

Remember that uniq only notices repeats that sit side by side, which is why the sorting step matters. This is a simulated shell over invented files: it understands a teaching subset of commands, and help lists them. When you have the password for level 8, run login 8 <password> or paste it into the answer box.