I would like to know if there is any command line tool to search text files preloaded with some well-known regexes (IP, email, date, path, url, xml tags, etc) so you could do something like:

grep -A 5 '443: open' somefile.log | getregexmatch --ip

To extract all the IP addresses from the output of grep.

  • What is the well-known regex for email? – MatthewRock Mar 7 '16 at 12:59
  • @StéphaneChazelas I want to extract the IP without cut, AWK and other similar tools im using right now – Hidden Mar 7 '16 at 13:03
  • @StéphaneChazelas You are right, thank you. – Hidden Mar 7 '16 at 13:10
  • Note that IP may not be a very good choice of an example here as there are so many ways to represent IP (IPv4 and IPv6) addresses. For instance, here, would that mean IPv4 addresses in quad-decimal (accepting leading 0s) notation or any standard representation of IPv4 or IPv6 IP addresses? Would it find a IP address in foo0.0.0.0bar or or (, or only as whole blank-separated words... – Stéphane Chazelas Mar 7 '16 at 13:56
  • @StéphaneChazelas I think IP is a perfect example. I know there are a thousand ways to represent IP, as there are a thousand ways to represent an email (using IP instead of a domain for example), a date (hypens or slashes) or path (back slash, fordward slash, escaped slashes, ...) but I'm not looking for a comprehensive list of regexes to cover every corner case (I know how to write my own regex for that scenarios), just a simple tool to save myself some typing on regular cases. – Hidden Mar 7 '16 at 14:15

Yes, perl is your friend. In this case perl's Regexp::Common in particular. It provides predefined regex definitions (see the documentation for more details : http://search.cpan.org/~abigail/Regexp-Common-2016020301/lib/Regexp/Common.pm).

An IPv4 example would be :

$ perl -MRegexp::Common -lne 'print $1 if /($RE{net}{IPv4})/g' file
  • Probably better with perl -MRegexp::Common -lne 'print for /$RE{net}{IPv4}/g' to return all the matches. – Stéphane Chazelas Mar 7 '16 at 16:57
  • @StéphaneChazelas good point. Will correct the answer. – KWubbufetowicz Mar 7 '16 at 17:28
  • Not exactly what I was looking for but probably the closest solution. Thank you both. – Hidden Mar 7 '16 at 21:25

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