How can an operator list all its history of commands in one step?（）

单项选择题An operator is asked to shutdown the telnet service for security reasons. What are the appropriate commands to achieve this?（）

A. comment out telnetd in /etc/services refresh -s inetd
B. comment out telnetd in /etc/inetd.conf refresh -s inetd
C. comment out telnetd in /etc/rc.tcpip refresh -s telnetd
D. comment out telnetd in /etc/inetd.conf refresh -s telnetd

单项选择题What command can be used to make all mountable filesystems available for use?（）

A. mount -a
B. automount all
C. varyonvg -m -a
D. run the /etc/filesystems script

单项选择题Which of the following will occur if an operator types the command vi file.out?（）

A. If the file exists it will be opened for editing. If the file does not exist an error message will be displayed.
B. If the file exists it will be opened for editing. If the file does not exist a new file with the name file.out will be created and opened for editing.
C. If the file exists an error message will be displayed. If the file does not exist a new file with the name file.out will be created and opened for editing.
D. If the file exists the operator will be asked whether to open the file or overwrite the file. If the file does not exist a new file with the name file.out will be created and opened for editing.

单项选择题The man page for command shows the following syntax: The man page for command shows the following syntax: command [ -a | -b ] Which of the following statements is true regarding this entry?（）

A. Either the -a or flag -b may be used, but not both.
B. If the flag -a is used then the flag -b also must be used.
C. One of the -a or -b flags must be used, but not both at the same time.
D. Both the flags may be used together, but neither are mandatory.

单项选择题An operator is editing a file using a keyboard without arrow keys. What key can be used to move the cursor one character to the right?（）

A. n
B. j
C. k
D. l