单项选择题
A.update /etc/rc.nfs
B.issue the chnfs command
C.recycle nfsd
D.unmount and remount the file systems
单项选择题 Whichcommandcanbeusedtoverifythatfilesystemsarebeingexportedbyaserver？（）
单项选择题 AgatewaymachinehasaccesstotheInternetandistryingtoreachamachineontheInternetcalledcactus.org.Althoughthegatewaymachinecannotreachcactus.org，anothernetworkacrosstownisabletoreachcactus.org.Furthermore，thegatewaymachinecanreachthenetworkacrosstown，butcannotpingthecactus.org.Whichofthefollowingtoolswillbesthelpdiagnosethelocationoftheproblem？（）
单项选择题 Whichofthefollowinglocalfilesisusedtorunthedatecommandontheremotemachine"Earth"usingthefollowingrexeccommandwithoutrequestforapassword？rexecEarthdate（）。