单项选择题
A.who /filesystem
B.lsfs /filesystem
C.fuser /filesystem
D.umount -f /filesystem
单项选择题 Asystemadministratorwantstoconfigureasystemsothatallnewuserswillbeputintothedatabasegroupbydefault.Howwouldthisbeaccomplished？（）
单项选择题 Asystemadministratorwouldliketomodifythesystemdefaultusercharacteristicssothateachnewuserwillnowbeassigned（bydefault）thecshshellratherthanthekshshell.Whichofthefollowingactionsshouldbeperformed？（）
单项选择题 Forsecurityreasons，anadministratorisaskedtomodifythesystemtopreventsomeonefromleavingaterminalloggedin.Toenableafiveminutetimeoutforallusers，whatwouldneedtobedonetoaccomplishthistask？（）