Unix/Lunix Programming

Exercise 7

In your CWD, make a text file called phone_number.txt that contains at least the following lines.

123 456-7891

123-456-78912

(123)-456-7890

123 456 7890

219-123-4567

(405) 456-7890

Exercise 8

Assume that a valid phone number has the format xxx-xxx-xxxx and each line in the text file does not contain leading or trailing white spaces.

Write a grep command that prints all valid phone numbers in phone_number.txt

Exercise 9

Now Assume that a valid phone number has the format (xxx) xxx-xxxx and each line in the text file does not contain leading or trailing white spaces.

Write a grep command that prints all valid phone numbers in phone_number.txt

Exercise 10

Now Assume that a valid phone number can have either the format xxx-xxx-xxxx or the format (xxx) xxx-xxxx.

Write a grep command that prints all valid phone numbers in phone_number.txt