The code 'if [ -z ${something} ]; then ... fi' means "if
${something} is an empty string, yell at the command line
about 'binary operator expected' and ignore the body of the
if statement, if ${something} is not an empty string,
the condition is false so ignore the body of the if
statement" which clearly isn't what the author wanted. Fix
it by adding a few quotes around the offending ${something}.