Control C is the standard way. It looks like Terminal maps cmd-. to
control c. You can probably map cmd-. to hex 0x03, but it might be
better to just get used to ^C since that works everywhere.
^\ sends sigquit, which sometimes works when sigintr doesn't.
command+. is a Mac-ism… which doesn't make it "wrong" just "non-standard" :-)
FWIW
TjL