How to delete duplicate lines in a file without sorting it in Unix?

Question

Is there a way to delete duplicate lines in a file in Unix?

I can do it with sort -u and uniq commands, but I want to use sed

Answer 1

This can be achieved using awk
Below Line will display unique Values

awk file_name | uniq

You can output these unique values to a new file

awk file_name | uniq > uniq_file_name

new file uniq_file_name will contain only Unique values, no duplicates