man grep says
grep [OPTIONS] PATTERN [FILE...] . . . --include=GLOB Search only files whose base name matches GLOB (using wildcard matching as described under --exclude).
So I typed
grep --include="*.html" 'li' *
to search for instances of
li in HTML files in the current directory. Instead I get a list of every use of
li anywhere in the directory, even in the non-HTML files. What am I doing wrong? I tried all kinds of variants like
grep --include=\*.html 'li' *
but without any luck.