I understand that it sorts and that output is used to find out the unique statement in the file. I also feel that uniq -u should print every unique statement in the file.

```
uniq -u data.txt

```

Output for this statement is:

```
MsxcvOe3PGrt78wpZG2bBNF5wfXpZhET
L0nxAwlfV9V3J5onKIT8KYQ9InTcQ7yE
4c7EsUtqLnLR9hiepV5EQVhdMgyi8onL
1drBmDT7PYS7hVgoTWkJSjUZUK7ZAIAa
L0nxAwlfV9V3J5onKIT8KYQ9InTcQ7yE
78rgduVcLZjLzZmooObdaN541MKV6IfQ
x0bga8Oxz5lgM8k52HrYy4ez7XJI0lM0
irGm6F73sbUrFhHukhp6JXgMQyLxJTz1

```

However when I run 

```
sort data.txt | uniq -u

```

Output is:
`UsvVyFSfZZWbi6wgC7dAFyFuR62324324324`

I am not able to understand why the first statement prints a list when there is only one line output.