Level 11: Binary Strings

You open data.txt and it's a nightmare. 801 lines of random-looking strings. At first glance, it looks like a dictionary attack waiting to happen, but then you realize the pattern: almost every line is a duplicate.

The goal is to find the one single line that exists alone. If you try to scroll through that list by eye, you're just fighting a losing battle against a screen of noise.

The trick here is to stop looking at the data and start looking at the frequency.

First, I used sort to group all the duplicates together. Once they're lined up, uniq -u becomes the MVP. While standard uniq just collapses duplicates, the -u flag tells the system: "Only show me the lines that occur exactly once."

sort data.txt | uniq -u

The noise disappears, and you're left with the only line that didn't have a twin.

Result: REDACTED

TL;DR: When you have a massive list of duplicates, don't hunt for the needle—filter out the hay with sort | uniq -u.