Merging identical lines in an output

Question

I'm trying to merge or not repeat the lines in an output using bash but don't want to grep for it. I'm not sure how to do it. I'm trying to do this in Linux:

Before:

113.171.10.13
113.171.10.13
113.171.10.13
113.171.10.13
23.253.228.76
23.253.228.76
23.253.228.76
23.253.228.76
23.253.228.76
23.253.228.76

After:

113.171.10.13
23.253.228.76

Any help is appreciated!

Thanks!

Answer 1

Use unique sort, outputing only the first of an equal run:

sort -u