Sometimes coloring a logfile or other gives a good overview when looking for stuff and behaviors
I just saw that grep have a coloring feature
This is an older question, but in case anyone is still looking, I recently created colorize, a tool which allows one to specify either fixed patterns or regular expressions to match with specific colors. It works out of the box with an intuitive syntax for specifying highlighting, and docopt as its only dependency.
colorize.py -f 'This is an interesting line=Blue' -f 'Different topic=Red' Input.log