test [ arg ... ]
[ [ arg ... ] ]
       Like the system version of test.  Added for  compatibility;  use
       conditional  expressions  instead  (see the section `Conditional
       Expressions').  The main  differences  between  the  conditional
       expression  syntax  and the test and [ builtins are:  these com-
       mands are not handled syntactically, so  for  example  an  empty
       variable  expansion  may cause an argument to be omitted; syntax
       errors cause status 2 to be returned instead of a  shell  error;
       and  arithmetic  operators  expect integer arguments rather than
       arithemetic expressions.
