SC1035

You need a space here

Problematic code:

if ![-z foo ]; then true; fi

Correct code:

if ! [ -z foo ]; then true; fi

Rationale:

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.

Contraindications

None.