In an experiment I was working on this weekend I needed to supervise a growing log file, looking for certain strings. In linux, we got the command tail, wich does exactly that, showing the last lines of a file and even taking care of the continous grow.

tail -f file

It's superb to look at logs like the ones generated by servers. The -f parameter is important, without it, tail would simply show the ten last lines of the file and finish.