What happens after issuing the command vi without any additional parameters?

Which of the following command sets the Bash variable named TEST with the content
FOO?

Which variable defines the directories in which a Bash shell searches for executable
commands?

Which of the following commands determines the type of a file by using a definition
database file which contains information about all common file types?

Which command is used in a Linux environment to create a new directory? (Specify ONLY
the command without any path or parameters.)

Which of the following commands prints all files and directories within the /tmp directory or
its subdirectories which are also owned by the user root? (Choose TWO correct answers.)

When running the command sed -e “s/a/b/” /tmp/file >/tmp/file While /tmp/file contains data,
why is /tmp/file empty afterwards?

When given the following command line. echo “foo bar” | tee bar | cat Which of the following
output is created?

Which of the following commands can be used to determine how long the system has been
running? (Choose TWO correct answers.)

Which of the following are valid stream redirection operators within Bash? (Choose THREE
correct answers.)