# leetcode\_193

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

## Solutions

1. **regex**
2. grep -P Perl like regex(used in python re module)

```bash
grep -P "^([0-9]{3}-|\([0-9]{3}\) )[0-9]{3}-[0-9]{4}$" file.txt
```