[LeetCode]#193. Valid Phone Numbers

Environment: bash

Key technique: grep

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.

Example:

Assume that file.txt has the following content:

987-123-4567
123 456 7890
(123) 456-7890

Your script should output the following valid phone numbers:

987-123-4567
(123) 456-7890

Analysis:

1. d{3}-\d{3}-\d{4}|\(\d{3} for 987–123–4567
2. (\d{3}\) \d{3}-\d{4} for (123) 456–7890

Solution:

\d{3}-\d{3}-\d{4}|\(\d{3}\) \d{3}-\d{4}

Submissions:

Reference:

https://leetcode.com/problems/valid-phone-numbers/discuss/843424/BASH-Easy-One-Liner