At this question in the answer from Kyle Brandt the [[ ]] construct is described as a "bash built-in test command". The following is shown as an example.
if [[ ( $a -gt 2 ) && ( $a -lt 5 ) ]]; then ... Why are double square brackets, literally [[ ]], necessary?
[[ is a much more versatile version of [ in bash.
For example, Using the [[ ... ]] test construct, rather than [ ... ] can prevent many logic errors in scripts. For example, the &&, ||, <, and > operators work within a [[ ]] test, despite giving an error within a [ ] construct.
also, their implementations are different
-bash-3.2$ type [ [ is a shell builtin -bash-3.2$ type [[ [[ is a shell keyword Refer here for a good explanation
[ "$this" > "$that" ] won't give an error, it'll just do something completely different from what you expected. (Specifically: it'll redirect output to the file specified by $this, then test whether $that is nonblank.)[[ ]] are equal to test keyword.
You can also use [ ] but [[ ]] isn't compatible with all shell types
To me, if I understand the real sense of question, question itself isn't well-formulated.
Those brackets have to be here not so much for order determination, but because the bash synopsis require them
Question is changed, so my answer too.
[[ ]] is used against [ ] because you don't have to worry about quoting the left hand side of the test that will be read as a variable.
Moreover, < and > doesn't need to be escaped
[ ], are you saying there is never a reason to use [[ ]].( ) determining the order of operations.
[[ ]] is better because you don't have to worry about quoting the left hand side of the test will be read as a variable. Moreover, < and > doesn't need to be escaped