Given a text file
file.txt that contains list of phone numbers (one per line), write a one liner bash script to print all valid phone numbers.
You may assume that a valid phone number must appear in one of the following two formats: (xxx) xxx-xxxx or xxx-xxx-xxxx. (x means a digit)
You may also assume each line in the text file must not contain leading or trailing white spaces.
file.txt has the following content:
Your script should output the following valid phone numbers:
# Read from the file file.txt and output all valid phone numbers to stdout.