watch is a tiny program that monitors a set of files and runs a command every time any one (or more) of them changes.

Installation

Run the following to install in $HOME/bin (PREFIX default value is /usr/local)

$ make install PREFIX=$HOME

Usage

For example, to run TeX every time you save a document file so you can see the changes immediately without any manual intervention, run the following:

$ watch *.tex - 'make document.ps'

Thanks to Ian Piumarta.