[fragmede]

inotifywait does a decent job of exposing the inotify primitive from the Linux kernel to userspace, but it's, well, primitive. Using that loop, if you change a file twice in quick succession, what happens? It'll trigger off the first change, but potentially ignore the second change if $2 takes longer to run than you can edit a file.

You can improve the basic loop somewhat, but a more thoroughly written program (whatever the language) rather than a 3 LOC loop is going to have more features and be more ergonomic. In particular, to truly be useful, it should be able to kill the command and restart it every time the file is saved.