if [ "$STUFF" = ""]; then
if [ "$STUFF" = "" ]; then
Bourne shells are very whitespace sensitive. Adding or removing spaces can drastically alter the meaning of a script. In these cases, ShellCheck has noticed that you're missing a space at the position indicated.
# shellcheck disable=SC1020 if [ "$STUFF" = ""]; then
ShellCheck is a static analysis tool for shell scripts. This page is part of its documentation.