Getting different results with the sort command

Question

Trying to sort a file with multiples occurring lines and return a text that only occurs once.

I am trying the over the wire game to increase my Linux proficient, but I run into a question...

In level 8 -> 9 the password for the next level is stored in the file data.txt and is the only line of text that occurs only once. I researched and came to the following answer:

 $ sort -cu data.txt

It printed a single output:

sort: data.txt:2: disorder: desthMrvBwFuSWkom7FP8ASJayNlfoRd

I expected sorting the file and returning a unique line, but I was not sure if it was the right one. So I did some more research, now using stackoverflow and others communities and find another solution:

$ sort data.txt| uniq -u

It printed a different output:

1 EN632PlfYiZbn3PhVK3XOGSlNInNE00t

I don't understand why the first command is not returning the right password, and returning a line that is repeated.

Answer 1

The -c option doesn't sort, it checks if the file is already sorted