[[expression]]
Korn shell only.  Same as test  expression or 
[expression],
except that [[  ]] allows additional operators.  Word
splitting and filename expansion are disabled.
Note that the brackets ([ ]) are typed literally.
Logical AND of test expressions.
Logical OR of test expressions.
First string is lexically "greater than" the second.
First string is lexically "less than" the second.
| This HTML Help has been published using the chm2web software. |