How to store the port number in this case?

Question

bash

There is a file with proxies (example):

127.0.0.1:8081
127.0.0.1:878
127.0.0.1:80
137.30.30.1:8080
137.30.30.1:80
127.0.0.1:878
137.30.30.1:8080

Sorting:

$ cat test.txt | sort -u
127.0.0.1:80
127.0.0.1:8081
127.0.0.1:878
137.30.30.1:80
137.30.30.1:8080

The result is expected, but not what is needed.
Let's try it differently:

$ cat test.txt | awk -F  ":" ' { print $1 } ' | sort -u
127.0.0.1
137.30.30.1

What you need! Only unique IPs remain, but.... No port numbers! How to be?

Answer 1

cat test.txt | sort -u | uniq

Answer 2

sort -k1 -t: < 1.txt