swatchdog - the Simple WATCHdog formerly known as swatch.

Swatchdog was originally written to actively monitor messages as they are
written to a log file via the UNIX syslog utility.  For a simple
demonstration type "perl swatchdog --examine=FILENAME" with FILENAME being
the file that you would like to see the contents of.  All this example will
do is demonstrate the different text modes that are available with to the
echo action.

WWW: http://swatch.sourceforge.net/