Sed command (Stream Editor)

We are giving expression inside single quote using sed command. I am using this example for all the use cases. Eg: ubuntu@ip-172-31-25-118:~$ cat data ID Name Salary Country 1 Pol 25000 India 2 Bont 45000 Belgium 3 Loki 55000 Germany 4 Hina 35000 Ind...