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:
987-123-4567 123 456 7890 (123) 456-7890
Your script should output the following valid phone numbers:
987-123-4567 (123) 456-7890
主要考察正则表达式的写法和awk的使用
awk '$0 ~ /^[0-9]{3}-[0-9]{3}-[0-9]{4}$|^([0-9]{3}) [0-9]{3}-[0-9]{4}$/ {print $0}' file.txt
遇到的问题:
1、$0就表示整行记录,因此不用使用FS=“ ”,$1来操作
2、awk的正则
先看下一段代码
awk '$0 ~ /^d{3}-d{3}-d{4}$|^(d{3}) d{3}-d{4}$/ {print $0}' file.txt
运行会发现是错误的,因此推测d在awk是非法的
3、正则表达式的分支(|)
4、^和$,如果不加会出错,比如下面的实例
0(101) 001-1223
0123-456-7891
123-456-78910
(001) 345-00001