​LeetCode刷题实战193：有效电话号码

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)

题意

示例

示例:

假设 file.txt 内容如下：
987-123-4567
123 456 7890
(123) 456-7890

你的脚本应当输出下列有效的电话号码：

987-123-4567
(123) 456-7890

解题

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

思路二：sed命令

sed -n -r '/^([0-9]{3}-|\([0-9]{3}\) )[0-9]{3}-[0-9]{4}$/p' file.txt