Log Parser is a very powerful, free and versatile tool that provides universal query access to text-based data, such as log files, XML files, and CSV files, as well as key data sources on the Microsoft Windows operating system, such as the event log, IIS log, the registry, the file system, and the Active Directory services.
Because the command-line interface is not very intuitive, I have created Log Parser Lizard, a FREE GUI tool for managing queries, exporting results to Excel, charts, etc… In addition I have added input filters for RegEx and log4net input log formats (with support for regular expressions) and SQL server T-SQL queries. There are some helpful examples included in installation package to help you start using Log Parser Lizard (and it’s SQL like syntax) for a web log analyzer and system log analyzer.
With LogParser you use Queries written in a dialect of the SQL language to specify the operations that transform input records generated by an Input Format into output records that are delivered to an Output Format. While many GUI tools are out there that provide filters, even those that allow the user to build custom filters can’t compare with the power of writing a custom SQL query in Log Parser. Log parser can accept most common log formats and output it into one of many formats of your choosing for analysis of relevant data.