基础匹配

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.

For example, assume that file.txt has the following content:

987-123-4567123 456 7890(123) 456-7890

Your script should output the following valid phone numbers:

987-123-4567(123) 456-7890

如下是用awk命令写的：

awk '{if($0 ~ /(^[0-9]{3}\-[0-9]{3}\-[0-9]{4}$)|(^\([0-9]{3}\) [0-9]{3}\-[0-9]{4}$)/ ) print $0}' file.txt