193. Valid Phone Numbers

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.

Input:

Assume that file.txt has the following content:

987-123-4567

123 456 7890

(123) 456-7890

Output:

Your script should output the following valid phone numbers:

987-123-4567

(123) 456-7890

# Read from the file file.txt and output all valid phone numbers to stdout.

grep -P '^(\d{3}-\d{3}-\d{4}|\(\d{3}\) \d{3}-\d{4})$' file.txt

Last updated 4 years ago

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