.PHONY: shellcheck
shellcheck: $(SCRIPTS) $(SHELLCHECKSCRIPTS)
if HAVE_SHELLCHECK
	[ -z "$(SCRIPTS)$(SHELLCHECKSCRIPTS)" ] && exit; shellcheck $$([ -n "$(SHELLCHECK_SHELL)" ] && echo "--shell=$(SHELLCHECK_SHELL)") --exclude=SC1090,SC1091$(SHELLCHECK_IGNORE) --format=gcc $(SCRIPTS) $(SHELLCHECKSCRIPTS)
else
	@[ -z "$(SCRIPTS)$(SHELLCHECKSCRIPTS)" ] && exit; echo "skipping shellcheck of" $(SCRIPTS) $(SHELLCHECKSCRIPTS) "because shellcheck is not installed"
endif
	@set -e; for dir in $(SHELLCHECKDIRS); do $(MAKE) -C $$dir shellcheck; done