Go back and accept only list of chars
@@ -39,13 +39,9 @@ unsetenv(Key) :-
shell(Command) :- shell(Command, 0).
shell(Command, Status) :-
- ( atom_si(Command) ->
- atom_chars(Command, CommandChars)
- ; Command = CommandChars
- ),
- must_be_chars(CommandChars),
+ must_be_chars(Command),
can_be(integer, Status),
- '$shell'(CommandChars, Status).
+ '$shell'(Command, Status).
pid(PID) :-
can_be(integer, PID),
