LPI - Linux Essentials

Would you use a standard release or a rolling release distribution for an enterprise Linux server installation?

Standard

What is the philosophical difference between OSI and FSF?

The FSF focuses on the ethics and rights restrictions of the software license over the practical benefits of the software itself.

What provides the basic utilities expected to exist on an operating system?

The GNU Core utilities

What is the PATH environment variable used for?

The PATH variable is the list of directories the shell will search for executables.

How is Linux installed in a virtualized environment?

Typically through conventional means, from installation media onto the abstracted bare metal.

What do permissions of 644 mean?

User: Read and write Group: Read Everyone: Read

NGINX and Apache are two common open-source ___ _______.

Web servers

What command could you use to view information about the system's processor?

cat /proc/cpuinfo

What is the basic format of a for loop?

for VARIABLE in SOMETHING do COMMANDS done

Which utility can be used to search for a pattern or string?

grep

What commands could you use to see the group membership of the user cloud_user?

groups cloud_user id cloud_user cat /etc/group | grep cloud_user

Which utility (by default) displays the first 10 lines of its input?

head

What command could you use to display command history?

history

What commands could you use to resolve www.example.com to an IP address?

host www.example.com dig www.example.com

What is the basic format of an if statement?

if [ SOME_TEST ] then SOME_COMMANDS fi

What command(s) could you use to view your IP address?

ifconfig ip addr show nmcli (if running NetworkManager)

What command would you use to open the info page for ls?

info ls

What command would you use to see all of the contents (but not ownership, permissions, ., or ..) of /tmp?

ls -A /tmp

What command would you use to list all files in a directory and nothing else?

ls -a

What command would you use to open the man page for ls?

man ls

What command could you use to reference the documentation of a CLI utility?

man or info, followed by the utility name

What command could you use to create a new directory called "Test" in the /tmp folder?

mkdir /tmp/Test

What command could you use to create a new empty directory named "Test" in your current working directory?

mkdir Test

Which utility can be used to count the number of words in a file?

wc

What can rpm-based systems use for package management?

yum dnf

What does the following command do? ip route show

'ip route show' displays the routing table.

What option would you use with ls to show permissions and ownership?

-l

What option would you use with the passwd command to lock an account?

-l

What file could you edit to map IP addresses to host names?

/etc/hosts

The CentOS Linux distribution is based on what other distribution?

Red Hat

Is ../../tmp a relative or absolute path?

Relative

What method/protocol do we use to securely connect to a remote Linux server?

SSH (Secure Shell)

Would you use Samba or NFS to share files with Windows users?

Samba. (Samba is a file sharing service that uses CIFS for compatibility with Windows devices.)

Shell scripts start with what sequence?

#!

To what variable would you add the path to a shell script so you could execute it without referencing the path?

$PATH

What environment variable is used for the shell prompt?

$PS1

In what root-level directory would you find folders for every running PID on the system?

/proc

What directory's contents are cleared upon system boot?

/tmp

In what folder will you find system logs?

/var/log

Root always has a UID of what?

0

What is the exit code of a command that ran successfully?

0

What would you type to save and quit a file that is open in vim?

:wq

What regular expression symbol would you use to match zero or one character?

? will match zero or one of the preceding characters. "Ap?le" would match "Ale" but not "Apple" (two p's). "App?le" would match "Apple".

What is a PID?

A PID is a process ID and is an integer.

Name two popular open-source web servers.

Apache NGINX

What is the difference between a system user and a regular user?

Apart from system users having a lower UID, system users normally don't have a login shell.

What is the default interpreter used on most Linux systems?

Bash (Bourne-Again Shell)

What are some common open-source programming languages?

C Java Javascript Perl Python PHP

How could you hide the file "file" from being shown in a directory listing?

Change it to .file

Open-source licensing and freedom (in terms of both use and cost) are permitting Linux to grow rapidly in the _____ and in ______________.

Cloud and virtualization

GPL is an example of what type of license?

Copyleft

When an open-source license is written such that any derivative works must use the same license, we call this ________.

Copyleft

What is the difference between permissive and copyleft?

Copyleft is more restrictive in terms of licensing derivative works.

What Linux distribution serves as the foundation for Ubuntu?

Debian

The Linux kernel, GNU core, X server, and GUI comprise a Linux ____________.

Distribution (The X server and GUI are optional.)

Raspberry Pi is what type of Linux system?

Embedded

For a user to be able to enter a directory, what level of access must they have?

Execute

When one open-source project is copied to form a new parallel project, we call that _______.

Forking

What does FLOSS stand for?

Free Libre Open-Source Software

What does FSF stand for?

Free Software Foundation

What open-source application might you use for a presentation?

Impress (OpenOffice or LibreOffice)

What will the following command do to the existing file "file1" in your current working directory? echo "" > file1

It will replace it with an empty file. To append to a file, you would want to use >>.

Which came first, OpenOffice or LibreOffice?

LibreOffice is a fork of OpenOffice; OpenOffice came first.

Unity, GNOME, and KDE are all examples of what?

Linux desktop environments

Where did MariaDB come from, and what is it?

MariaDB was forked from MySQL as a database server application.

Are user passwords stored in /etc/passwd?

No. The hashes are stored in /etc/shadow.

What would the following line do if placed in a shell script? # rm -rf *

Nothing — it's a comment ;-)

What happens to files in /var/tmp upon system boot?

Nothing. The contents of /tmp are cleared upon system boot, but the contents of /var/tmp are not.

What happens to a symbolic link if the target file is moved or deleted?

Nothing; the link persists but the old destination is no longer reachable.

What are OwnCloud and NextCloud?

OwnCloud and NextCloud are open-source cloud applications that function like DropBox.

What do we call the collection of data centers that provide compute, application, and storage services over the internet?

The cloud!

What source does a Linux distribution typically use for installations?

The distribution's software repository.

Debian-based systems use what package file format and what management tools?

The package file format is dpkg. The package management tool is apt.

Red Hat-based systems use what package file format and what management tools?

The package file format is rpm. The package management tool is yum (or dnf, in the case of Fedora).

Which utilities can be used to print the contents of a file to the screen?

cat less more

What does 'cloud_user@ip-10-0-1-10 $' in the console mean?

The user cloud_user is logged into the host ip-10-0-1-10, and the shell is running with normal user privileges ($) and ready for commands.

How is Linux provisioned in the cloud?

Through the Linux images supplied by the cloud provider.

What is the purpose of a free-software license?

To establish the terms of modification and redistribution.

Which utility (by default) displays the last 10 lines of its input?

tail

Does everyone have execute permission on a file if it is given 755 permissions?

Yes, 755 is rwxr-xr-x.

What can dpkg-based systems use for package management?

apt

What command could you use to view kernel messages?

dmesg

What command could you use to view motherboard information?

dmidecode

What is the passwd command used for?

passwd is used for changing passwords and locking accounts.

What command(s) could you use to view all running processes?

ps aux ps -eF (lots of other options)

What command would you use to print the current working directory to the screen?

pwd

What command could you use to remove all files starting with the text "file_" from the /tmp directory?

rm /tmp/file_*

How can a regular user elevate permissions for a particular command (if granted the ability in the /etc/sudoers file)?

sudo

What utility can you preface a command with to execute with elevated privileges?

sudo

What command could you use to unpack ./archive.tar?

tar xf ./archive.tar

What would the following command do to the file archive.tar in your current working directory? tar xvf archive.tar

tar xvf will extract (verbosely) the file archive.tar.

What command could you use to unpack the gzip-compressed archive ./archive.tgz?

tar xzf ./archive.tgz

What command could you use to create a new empty file named "file1" in your current working directory?

touch file1

What command(s) could you use to create a new and empty file named "newfile" in the current working directory?

touch newfile echo "" > newfile

What command will create the user 'tester' and the home directory at the same time with defaults?

useradd -m tester

Does the useradd command create the home directory by default?

useradd merely sets the home directory in /etc/passwd; it doesn't create it by default.

What command would you use to delete the user 'tester'?

userdel tester