Colorize Monitoring of Logs

Generic Colouriser (grc):

Works with many different file formats.

Example:

grc tail -f /var/log/apache/access.log /var/log/apache/error.log

Multitail:

Works with even more file formats :) And is more of a full blown "tail" with multi windows, diff outputs etc.. Very useful.

Examples:

Merge 2 logfiles in one window:

multitail /var/log/apache/access.log -I /var/log/apache/error.log

In one window show all new TCP connections and their state changes using netstat while in the other window displaying the merged access and error logfiles of apache

multitail -R 2 -l "netstat -t" /var/log/apache/access.log -I /var/log/apache/error.log

Check out CCZE, it does the job for me. You have a choice of curses, ansi and html output.

Check out glTail (http://www.fudgie.org/). Does way more than you're asking, but maybe that's OK

Monitor '/applications' highlighted;

tail -f /var/log/system.log | grep /Applications --color

Colorize is very good tool for simply piping your text through another filter to get fancy ANSI colors. In fact, it's one simple 4kB perl script (almost half of it is just documentation) and it's based on regular expressions.

You can highlight whole line containing given patern (good for hiding unwanted debug logs or highlighting Exceptions) or just highlight pattern in uncolored line (highlighting http response codes).

I have several presets for various file types in separate runnable files. Then I just run mvn clear install | colorbuild, tail -f *.log* | colorlog or svn diff | colordif to have really fancy output.