Today's #FreeSoftwareAdvent is a double whammy of shell-based "checking" utilities.
linkchecker (https://linux.die.net/man/1/linkchecker; probably get it from your distro) checks websites (recursively, as you wish) for broken links.
shellcheck (https://www.shellcheck.net/; available in browser or as a terminal tool) checks bash and other shell scripts for bugs.
Very simple, single purpose, very useful, tools.