05 August 2008
Given a text file file.txt that contains a 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
```shell script grep ‘^(([0-9]{3}) |[0-9]{3}-)[0-9]{3}-[0-9]{4}$’ file.txt
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```shell script
sed '/^\(([0-9]\{3\}) \|[0-9]\{3\}-\)[0-9]\{3\}-[0-9]\{4\}$/!d' file.txt