Bash: [: =: unary operator expected
[: =: unary operator expected
Use:
if [ "$aug1" = "and" ];
because otherwise, if $aug1 is undefined or empty, it vanishes from the scene of the crime, leaving only
if [ = "and" ];
which is not valid.
With the modern [[
, you don’t need to worry about that. It has lots of other nice features, too.