[Bash]LeetCode193. 有效电话号码 | Valid Phone Numbers

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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

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给定一个包含电话号码列表（一行一个电话号码）的文本文件 file.txt，写一个 bash 脚本输出全部有效的电话号码。

你能够假设一个有效的电话号码必须知足如下两种格式： (xxx) xxx-xxxx 或 xxx-xxx-xxxx。（x 表示一个数字）

你也能够假设每行先后没有多余的空格字符。

示例:

假设 file.txt 内容以下：

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

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8ms

1 # Read from the file file.txt and output all valid phone numbers to stdout.
2 grep -P '^(\d{3}-|\(\d{3}\) )\d{3}-\d{4}$' file.txt

---

12ms

1 # Read from the file file.txt and output all valid phone numbers to stdout.
2 
3 grep -P '^\([0-9]{3}\)\s[0-9]{3}-[0-9]{4}$|^[0-9]{3}-[0-9]{3}-[0-9]{4}$' file.txt

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12ms

1 # Read from the file file.txt and output all valid phone numbers to stdout.
2 sed -n -r '/^([0-9]{3}-|\([0-9]{3}\) )[0-9]{3}-[0-9]{4}$/p' file.txt

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12ms

1 # Read from the file file.txt and output all valid phone numbers to stdout.
2 egrep "(^[0-9]{3}-[0-9]{3}-[0-9]{4}$)|(^\([0-9]{3}\)\s[0-9]{3}-[0-9]{4}$)" file.txt