time sensative ( stuck on question 4)

Create the text file shown below and call it file1. It contains name, phone number and income in three different fields separated by tab. The income starts with a dollar sign. There are two blank lines after the name Steve. John 111-222-3333 $45000 David 888-999-2323 $3400 Steve 800-777-1212 $2450 Mike 400-89-23 $4567 Write a sed command to get rid of the blank lines and save the result in a new file called file2. Write a sed command to replace the $ if it follows one or more digits with empty (i.e. remove the $ using substitute command) in file2. Save the result in file3. Write a sed command to replace the first six digits of the phone number with xxx-xxx (if the number is a valid phone number) in file3. Save the result to file4