Which of the following commands lists all defined variables and functions within Bash?

A. env

B. set

C. env -a

D. echo $ENV

Which of the following commands puts the output of the command date into the shell variable mydate?

A. mydate="$(date)"

B. mydate="exec date"

C. mydate="$((date))"

D. mydate="date"

E. mydate="${date}"

The correct crontab entry to execute the script chklog three times per month between 3 p.m. and 5 p.m.:

A. * 3,4,5 1 * * chklog

B. 3 3,4,5 1 * * chklog

C. 3 15,16,17 * * * chklog

D. 0 15,16,17 1 * * chklog

E. * 15,16,17 1 * * chklog

What is true about the file /etc/localtime?

A. It is a plain text file containing a string such as Europe/Berlin

B. It is created and maintained by the NTP service based on the location of the system's IP address.

C. It is a symlink to /sys/device/clock/ltime and always contains the current local time.

D. After changing this file, newtzconfig has to be run to make the changes effective.

E. It is either a symlink to or a copy of a timezone information file such as /usr/share/zoneinfo/Europe/Berlin.

What entry can be added to the syslog.conf file to have all syslog messages generated by a system displayed on console 12?

A. *.* /dev/tty12

B. /var/log/messages | /dev/tty12

C. | /dev/tty12

D. syslog tty12

E. mail.* /dev/tty12

Which of the following keywords can be used in the file /etc/nsswitch.conf to specify a source for host name lookups? (Choose TWO correct answers.)

A. resolv

B. dns

C. remote

D. files

E. hosts

When trying to unmount a device it is reported as being busy. Which of the following commands could be used to determine which process is causing this?

A. debug

B. lsof

C. nessus

D. strace

E. traceroute

What is a purpose of an SSH host key?

A. It must be sent by any SSH client in addition to a user key in order to identify the client's host.

B. It provides the server's identity information to connecting SSH clients.

C. It is the root key by which all user SSH keys must be signed.

D. It authenticates any user that logs into a remote machine from the key's host.

E. It is used by system services like cron, syslog or a backup job to automatically connect to remote hosts.

Which of the following entries in /etc/syslog.conf writes all mail related events to the file /var/log/maillog and sends all critical events to the remote server logger.example.com?

A. mail.*/var/log/maillogmail,crit@logger.example.org

B. mail.*/var/log/maillogmail.critsyslog://logger.example.org

C. mail/var/log/maillogmail.crit@logger.example.org

D. mail.*/var/log/maillogmail.crit@logger.example.org

E. mail */var/log/maillogmail crit@logger.example.org

With X11 forwarding in ssh, what environment variable is automatically set in the remote host shell that is not set when X11 forwarding is not enabled? (Specify only the environment variable without any additional commands or values.)

A. DISPLAY

B. $DISPLAY

C. PlaceHolder

D. PlaceHolder