A.It sends messages to the command lines of all current user sessions.

B.It might not display older information because it was overwritten by newer information.

C.It displays the content of the Linux kernel's ring buffer.

D.It traces the execution of a command and shows each step the program carries out.

E.It immediately outputs all new messages written to the system journal.

A.man ls

B.usage ls

C.manual ls

D.option ls

E.info ls

A.$

B.%

C.*

D.+

E.?

A./dev/sdais a hard disk device while /dev/ssdais a solid state disk.

B.Solid state disks provide faster access to stored data than hard disks.

C.Solid state disks can store many times as much data as hard disk drives.

D.Hard disks can fail due to physical damage, while solid state disks cannot fail.

E.Hard disks have a motor and moving parts, solid state disks do not.

A.$PATH=/new/dir: $PATH

B.export $PATH=/new/dir: $PATH

C.export PATH=/new/dir: PATH

D.PATH=/new/dir: PATH

E.export PATH=/new/dir: $PATH