Add double quotation on duplicated name

Question

I want to find duplicated name from the file like below and marked them with \"\".

file:

James Miki:123-456-7890
Wang Tai:  234-563-6879
James Miki: 123-         


        

Answer 1

Another alternative using sed + sort + uniq pipeline:

cat file | sed 's/^\(.*\) *: */"\1": /' | sort | uniq -d

The output:

"James Miki": 123-456-7890