ASSESSMENT QUESTIONS SOLUTIONS
GRADED A+
◉ From the Console (The keyboard and monitor attached to a
computer running Linux).
Answer: Press the following key combinations:
Ctrl+Alt+F1 (in some Linux distributions, Alt+F1) will start or switch
to the first Linux shell session.
Ctrl+Alt+F2 through Ctrl+Alt+F6 (in some Linux distributions,
Alt+F2 through Alt+F6) will switch to the second through sixth shell
sessions.
While Linux distributions will vary, in most cases when a GUI is
installed, it will use the first console session. Use Ctrl+Alt+F1 to
switch to a graphical login screen. If you are already logged in,
Ctrl+Alt+F7 will switch to the desktop GUI.
◉ From a desktop GUI.
Answer: Open a terminal session from the applications menu.
◉ sh.
Answer: The Bourne shell is the oldest Linux shell, but is not widely
used. This shell was developed for UNIX in the 1970s.
,◉ bash.
Answer: The Bourne-again shell (Bash) is the default shell used by
most Linux distributions. It uses commands similar to a UNIX shell.
The Bash includes:
Command and file name completion when pressing the Tab key
Command history
◉ zsh.
Answer: The Z Shell (zsh) is an improved version of Bash and is
available on many Linux distributions.
◉ shh.
Answer: The Bourne shell (sh) is an earlier version of bash, and is
similar in many ways. The sh shell was originally created by Steve
Bourne.
◉ ksh.
Answer: The Korn shell (ksh) provides scripting features not found
in Bash. Ksh was developed by David Korn.
◉ csh.
Answer: The C-shell (csh) uses syntax similar to the syntax used in
the C programming language.
,◉ tcsh.
Answer: The tcsh shell is an improved version of csh. It offers
command line editing and completion features that are not available
in csh.
◉ /etc/shells.
Answer: If a shell type is installed, it will be listed in the /etc/shells
file. You can switch to any shell by typing the shell's name. For
example, type ksh within any shell to switch to the Korn shell.
◉ echo $SHELL.
Answer: The echo $SHELL command returns the default or
preferred shell. The environment $SHELL holds the user's preferred
shell which is typically set in /etc/passwd. For example, if bash is the
user's preferred shell, $SHELL will hold the value, /bin/bash. The
preferred shell does not change when you switch shell types.
◉ echo $0.
Answer: The echo $0 command can be used to return the current
shell type. The special variable $0 normally holds the command used
to start a script. A shell session is initiated by a script. Consequently,
$0 will hold the name of the script which is consistent with the shell
type. For example, $0 in a console session running bash might hold
the value -bash, $0 in a terminal application opened from a desktop
, menu might hold the value bash. When you type ksh, the ksh script
is run, a Korn shell session is opened and $0 will hold the value ksh.
◉ all shells share some common characteristics:.
Answer: The shell provides a command line interface that allows the
user to interact with the Linux kernel.
A Linux system can run multiple shell sessions at the same time.
One shell session can run within another shell session. This may be
done interactively, such as when a user starts a second shell from the
first shell's command line, or automatically, by scripts or programs.
Shells use configuration files to establish their operating
environments.
◉ bash shell default command line prompt.
Answer: The username of the current user
The @ symbol
The hostname
A space
The base name of the current working directory
◉ ~.
Answer: If the current working directory is the home directory (the
default directory when the user first logs in), the tilde symbol (~) is
displayed instead.