A system administrator is unable to unmount a file system. Which is the appropriate command to determine who or what is accessing the file system？（）

单项选择题Asystemadministratorwantstoconfigureasystemsothatallnewuserswillbeputintothedatabasegroupbydefault.Howwouldthisbeaccomplished？（）

A.remove all other groups from the system
B.run the command mkuser -default "GROUP=database"
C.change the default group in /usr/lib/security/mkuser.default
D.edit /etc/security/group to move all users to the database stanza

单项选择题Asystemadministratorwouldliketomodifythesystemdefaultusercharacteristicssothateachnewuserwillnowbeassigned（bydefault）thecshshellratherthanthekshshell.Whichofthefollowingactionsshouldbeperformed？（）

A.Run the command chlogin -shell "csh"
B.Run the command mkuser -default "SHELL=csh"
C.Edit /etc/passwd and change all "ksh" entries to "csh"
D.Modify the contents of /usr/lib/security/mkuser.default file

单项选择题Forsecurityreasons，anadministratorisaskedtomodifythesystemtopreventsomeonefromleavingaterminalloggedin.Toenableafiveminutetimeoutforallusers，whatwouldneedtobedonetoaccomplishthistask？（）

A.Add the following line to /etc/environment：  TMOUT=300
B.Add the following lines to /.profile  TMOUT=5  export TMOUT
C.Execute the following command：  chuser -u ALL -a TIMEOUT=5M
D.Execute the following command：  chsec -u ALL -a TIMEOUT=600

单项选择题WhichactionchangesthedefaulteditorforALLusersonthesystemfromvitoeditofthefollowing？（）

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？（）

A.mkuser
B.cruser
C.adduser
D.edit /etc/password