awk regex can't match ip addresses when trying to find repeating digits
awk, regex
Solution
To use `interval` `{1,3}` with `gnu awk` you my need to enable it with `--re-interval` like this:
awk --re-interval '/[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}/{print $0}' maillog
Problem
I can't get the following to match any IP addresses ``` awk '/[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}/{print $0}' maillog ``` or this one... ``` awk '/[[:digit:]]{1,3}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}/' maillog ``` but this works... ``` awk '/127.0.0.1/{print $0}' maillog ``` and so does this... ``` awk '/[0-9]+\.[0-9]+\.[0-9]+\.[0-9]/{print $0}' maillog ``` What am I doing wrong in the first two?