单项选择题 Whichofthefollowingcommandswouldasystemadministratorruntovalidate/etc/tunables/nextbootaftermanuallyediting（）

单项选择题 Howcanasystemadministratordetermineifasystemisrunningin32-bitor64-bitmode（）

单项选择题 Following a system boot， the display indicates that previously detected hardware is missing.  Which of the following commands would identify the missing hardware（）