单项选择题
A.Issue the command： export EDITOR=/usr/bin/edit
B.Modify /.profile and change the EDITOR variable to /usr/bin/edit
C.Modify /etc/environment and add EDITOR=/usr/bin/edit export EDITOR
D.Modify /etc/security/defaults and change the EDITOR value to /usr/bin/edit
单项选择题 Howdoesasystemadministratoraddanewusertoasystem？（）
单项选择题 Auserwantstobepermanentlyaddedtothedbagroup.Whichcommandorprocesscanbeusedtoaccomplishthis？（）
单项选择题 Duetooperationalcommitments，asystemhasaveryshortbackupwindowduringtheweek，butisnotusedfromSaturdaymorningthroughSundayatMidnight.Whichofthefollowingminimizesbackuptime，whileprovidingthebestdatarestorecoverage？（）