Glogg is a multi-platform GUI application that helps browse and search through long and complex log files. It is designed with programmers and system administrators in mind and can be seen as a graphical, interactive combination of grep and less.

The tool enables you to use regular expressions to search for interesting events in your log files. It presents a results window which, together with complex regular expressions allows easy isolation of the meaningful lines amongst the noise.

glogg has been primarily developed to help spot and understand problems in huge logs generated by embedded systems. It can be equally useful to a sysadmin digging through logs from databases or web servers.The main design goals for glogg are:

• it should be fast
• it does not have any limit on the size of files it can handle
• it provides a clear view of the matches even in heavily cluttered files.

Main features include the following:

• Runs on Unix-like systems, Windows and Mac thanks to Qt
• Provides a second window showing the result of the current search
• Supports grep/egrep like regular expressions
• Colorizes the log and the search results
• Displays a context view of where in the log the lines of interest are
• Is fast and reads the file directly from disk, without loading it into memory
• Follows a log that is written to disk in real time
• Allow to insert marks in the logs to interesting lines
• Supports vim/less like keyboard commands to move around the file
• Is open source, released under the GPL

You can read more and download this tool over here: https://github.com/nickbnf/glogg