RE: wrong logical evaluation of expressions involving true or falsecommands

[Andrew Neitsch]

'help test' says that an expression consisting of a single string is an alias 
for "-n STRING" which is "true if the string is not empty." So, [ false -a 
false ] and [ false ] are true because "false" is a non-empty string. [ "" ] is 
false.

You probably just want 'true && false' without the [.