@item shell @var{command string}
@kindex shell
@cindex shell escape
-Invoke a shell to execute @var{command string}. If it exists, the
-environment variable @code{SHELL} is used for the name of the shell to
-run.
+Invoke a the standard shell to execute @var{command string}.
@ifclear DOSHOST
-Otherwise @value{GDBN} uses @code{/bin/sh}.
+If it exists, the environment variable @code{SHELL} determines which
+shell to run. Otherwise @value{GDBN} uses @code{/bin/sh}.
@end ifclear
@end table