#numerical comparison
$ (( 9 > 10 )) && echo A
$ [[ 9 -gt 10 ]] && echo A
$
#string comparison
$ [[ 9 > 10 ]] && echo A
A

But environment variable LANG affects LOCALE:

$ export LANG=en_US	#or en_US.UTF-8, as used by Oracle
$ [[ a > A ]] && echo A	#even though 'a' has ASCII 97 while 'A' has 65
$
$ export LANG=C		#make it behave "normal"
$ [[ a > A ]] && echo A
A

Interestingly, setting LANG to some garbage will have no effect; whatever has (or does 
not have) effect as of now still has (or does not have) effect.



(Test done in 4.1.2(1)-release (x86_64-redhat-linux-gnu), but may be version-independent.)