grep with regex for phone number

Question

I would like to get the phone numbers from a file. I know the numbers have different forms, I can handle for a single one, but don\'t know how to get a uniform regex. For ex

Answer 1

We can put all the required phone number validations one by one using an or condition which is more likely to work well (but tiresome coding).

grep '^[0-9]\{10\}$\|^[0-9]\{3\}[-][0-9]\{3\}[-][0-9]\{4\}$\|^[0-9]\{3\}[ ][0-9]\{3\}[ ][0-9]\{4\}$\|^[(][0-9]\{3\}[)][0-9]\{3\}[-][0-9]\{4\}$' phone_number.txt

returns all the specific formats :

• 920-702-9999
• (920)702-9999
• 920 702 9999
• 9207029999

Answer 2

There are usually four patterns of phone numbers

1. xxx-xxx-xxxx         grep -o '[0-9]\{3\}\-[0-9]\{3\}\-[0-9]\{4\}'  file.txt
2. (xxx)xxx-xxxx        grep -o '([0-9]\{3\})[0-9]\{3\}\-[0-9]\{4\}'  file.txt
3. xxx xxx xxxx         grep -o '[0-9]\{3\}\s[0-9]\{3\}\s[0-9]\{4\}'  file.txt
4. xxxxxxxxxx           grep -o '[0-9]\{10\}' file.txt

In all

grep -o '\([0-9]\{3\}\-[0-9]\{3\}\-[0-9]\{4\}\)\|\(([0-9]\{3\})[0-9]\{3\}\-[0-9]\{4\}\)\|\([0-9]\{10\}\)\|\([0-9]\{3\}\s[0-9]\{3\}\s[0-9]\{4\}\)' file.txt

Of course, one could simplify the regex above but we can also leave this simplification to grep itself ~

Answer 3

My first thought is that you may find it easier to see if your candidate number matches against one of four regular expressions. That will be easier to develop/debug, especially as/when you have to handle additional formats in the future.

Answer 4

Try this one:

^(\d{10}|((([0-9]{3})\s){2})[0-9]{4}|((([0-9]{3})\-){2})[0-9]{4}|([(][0-9]{3}[)])[0-9]{3}[-][0-9]{4})$

This is only applicable for the formate you mention above like:

1. xxxxxxxxxx
2. xxx xxx xxxx
3. xxx-xxx-xxxx
4. (xxx)xxx-xxxx

Answer 5

grep -P '[0-9]{3}-[0-9]{3}-[0-9]{3}|[0-9]{3}\ [0-9]{3}\ [0-9]{3}|[0-9]{9}|\([0-9]{3}\)[0-9]{3}-[0-9]{3}'

Answer 6

grep '\(([0-9]\{3\})\|[0-9]\{3\}\)[ -]\?[0-9]\{3\}[ -]\?[0-9]\{4\}' file

Explanation:

([0-9]\{3\}) three digits inside parentheses

\| or

[0-9]\{3\} three digits not inside parens

...with grouping parentheses - \(...\) - around the alternation so the rest of the regex behaves the same no matter which alternative matches.