Run arbitrary commands when files change. More information: https://github.com/watchexec/watchexec.
ls -la when any file in the current directory changes:watchexec ls -la
make when any JavaScript, CSS and HTML file in the current directory changes:watchexec --exts js,css,html make
make when any file in the lib or src directory changes:watchexec --watch lib --watch src make
my_server when any file in the current directory changes, sending SIGKILL to stop the child process:watchexec --restart --stop-signal SIGKILL my_server