--- title: "Regular Expressions And Log Parsing" url: "https://osherove.com/blog/2003/4/27/regular-expressions-and-log-parsing.md" canonical: "https://osherove.com/blog/2003/4/27/regular-expressions-and-log-parsing.html" published: "2003-04-27T18:12:00" updated: "2003-04-27T18:12:00" tags: [".Net Original"] author: "Roy Osherove" description: "My company needs a small utility to parse log files generated by some of the speech engines we are using in our products. They generate old-style ASCII log files that are easy to read but cumbersome to parse. I started…" usage: "Licensed under CC BY 4.0 — reuse, quote and adapt with attribution (Roy Osherove, link to the original page)." license: "https://creativecommons.org/licenses/by/4.0/" --- # Regular Expressions And Log Parsing By Roy Osherove April 27, 2003 In [.Net Original](https://osherove.com/blog/category/net-original) **Historical article** · Originally published April 27, 2003; technical details may be outdated. My company needs a small utility to parse log files generated by some of the speech engines we are using in our products. They generate old-style ASCII log files that are easy to read but cumbersome to parse. I started playing around with regular expressions ,  and found a treasure! Boy was i missing out on something really powerful or what? Using Regex I was able to create a small LogToXML converter class in just under 2 hours (with almost no prior experience with regular expressions before!). it is amazing. I'm currently trying to write this whole experience out as an article to CodeProject. Hopefully out in the next couple of days. Using [Expresso](http://www12.brinkster.com/ultrapico/Expresso.htm) really teaches you stuff about the possibilities just by poking around on all the optin tabs. The thing i love about this the most is that i keep finding out cooler stuff about Regex. For instance - I can create named groups to use for my parsing. As an example i'll show you a line from my Babylon -Pro translator and Thesaurus Log file: It contains this line: **26/4/03 23:43:52 4.0.2.3:Roy:3004984200 - warning 998: Error opening file 'C:\\Program Files\\Babylon\\ocr\_data' "rb" - (Path not found)** using this (kinda scary) regular expression, i can parse this into names fields and go over them using the Match Object provided by the .Net Framework: **(?(?\\d{1,2})/(?\\d{1,2})/(?(?:\\d{4}|\\d{2}))(?x))\\s(?