[iigs]

That looks like it was a sample line that wasn't particularly useful, but if you do:

cat file.txt | sort | uniq | wc -l ## notice uniq

it gives you the count of unique lines. If you omit the sort in that instance it will fold duplicates together a/b/a is three lines, not two.

[gnosis]

Instead of "sort | uniq" you could just use "sort -u"