Watch Command – How to Scroll Within the Output of Watch Command

Depending on your implementation/version of watch, it may not start a shell to interpret a command line, but instead runs a command that takes as argument the arguments it received itself. So, in that case, if you need it to run a shell command line, you need to start a shell explicitly as in:

watch sh -c 'find . | wc -l'

See also the inotifywait -rm . command (if on Linux) to monitor activity in a directory.

Also note that find . | wc -l only returns the number of files (excluding the .. entries) if the file names don't contain newline characters. If that may be a problem, you could do:

find .//. | grep -c //

Also note that there's no GNU or Unix utility by the name of watch. There's a watch command in the procps suite of tools for Linux, there's a watch implementation in busybox. On BSDs, watch does something completely different. watch is not a standard command (in none of POSIX, Unix or LSB specifications).

You can use the -t switch to watch which causes it not to print header. However, that will still clear the screen so you might be better off with a simple shell loop:

while sleep 1; do
    wc -l my.log
done

One of the advantages is, that you can easily add other commands (e.g. date) and/or pipe the output through sed to reformat it. By the way, if you swap sleep 1 with wc in the loop, it will automatically terminate on errors.