How to transfer ip using sed and substitute before a comma?

Question

Software testing

There is a 1.txt file with the following content:

mail.yandex.net,

mail.mail.ru,
88.88.88.88
mail.mail1.ru,
mail.asdl2.ru,
mail.asd.ru,
77.77.88.88
....

I I want to substitute IP before a comma. As a result, I want to get such a file.

mail.yandex.net,

mail.mail.ru, 88.88.88.88
mail.mail1.ru,
mail.mail2.ru,
mail.mail3.ru, 77.77.88.88
....

Answer 1

Yandex.Tank, Siege, JMeter

Answer 2

Loaddy.com - the only load testing service in Russian

Answer 3

$ awk '!/,$/{x=x$0}x!=""{print x;x=""}/,$/{x=$0}' 1.txt
mail.yandex.net,
mail.mail.ru,88.88.88.88
mail.mail1.ru,
mail.asdl2.ru,
mail.asd.ru,77.77.88.88