单项选择题
All of the following commands could be used to verify availability of tty devices on the system EXCEPT：（）。
A.lstty B.lscons C.lsdev D.lscfg
单项选择题 Whatisthepurposeof/etc/uucp/Devices？（）
单项选择题 Whichofthefollowingcommandsgathersnetworkpacketstatistics？（）
单项选择题 Whichofthefollowingflowcontrolsettingsallowsresumptionofsuspendedoutputbyhittingthe"R"key？（）
