As we discussed in Chapter 20, the following two commands fi nd all the lines in the fi le data that contain at least one non-alphabetic character: What command would you use to fi nd all the lines...

As we discussed in Chapter 20, the following two commands fi nd all the lines in the fi le data that contain at least one non-alphabetic character:

What command would you use to fi nd all the lines that do not contain even a single alphabetic character?