I've looked at some of the other IP matching that seems a lot more complex but several of them don't work, and I'm too simple minded to figure out why. Keep it simple, I've never had a problem matching IP addresses in logs with this one.

Validates input to match UK Date Time standard

matches the exact fields of CSV files supports: qouted fields quoted fields containing commas, doubble quoutes, and newlines empty fields empty records arbitrary white space in, and outside quoted fields

12

Validate an ivoice number with the last two digit as last 2 year digit

Matches all the RGB colors in the format #RRGGBB and #RGB

How to match the first line of a xml document

Will find lines that end with "/*.config"

This regex matches "bob" but does not match "abob", "bobb" or "cbobd" while it does match "cbob" and "bobd". Here "bob" is the dirty word and "abob", "bobb" and "cbobd" are safe phrases

Matches current mobile telephone numbers in Spain.

Matches current mobile phone numbers in Italy