Question 1

When the command echo $$ outputs 12942, what is the meaning of 12942?

Options :

A : It is the process ID of the echo command.

B : It is the process ID of the current shell.

C : It is the process ID of the last command executed.

D : It is the process ID of the last command which has been placed in the background.

Answer: B

Question 2

What is a purpose of an SSH host key?

Options :

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.

Answer: B

Question 3

Which of the following statements is correct regarding the command foo 1> bar?

Options :

A : The stdout from the command foo is appended to the file bar.

B : The stdout from the command foo overwrites the file bar.

C : The commandfoo receives its stdin from the file bar.

D : The command foo receives its stdin from the stdout of the command bar.

E : The stderr from the command foo is saved to the file bar.

Answer: B

Question 4

Each entry in a crontab must end with what character?

Options :

A : Tab

B : Space

C : Backslash

D : Newline

Answer: D

Question 5

When running the command

sed -e "s/a/b/" /tmp/file >/tmp/file

While /tmp/file contains data, why is /tmp/file empty afterwards?

Options :

A : The file order is incorrect. The destination file must be mentioned before the command to ensure redirection.

B : The command sed did not match anything in that file therefore the output is empty.

C : When the shell establishes the redirection it overwrites the target file before the redirected command starts and opens it for reading.

D : Redirection for shell commands do not work using the > character. It only works using the | character instead.

Answer: C