Linux Essentials (010-160)

CentOS

A Linux distribution that is compatible with Red Hat Enterprise Linux but does not offer the paid support that Red Hat does. Essentially compiled RHEL open-source code.

Ubuntu

A community-developed Linux-based operating system with a GUI similar to that of Windows.

Linux distribution

A complete Linux implementation, including kernel, shell, applications, utilities, and installation media, that is packaged, distributed, and supported by a software vendor.

Linus Torvalds

A finnish graduate student who coded and created the first version of Linux and subsequently distributed it under the GNU Public License.

GIMP

A free open source photo editing program that is often compared to Photoshop. (GNU Image Manipulation Program)

Command line interpreter

A program that accepts typed commands from the keyboard and performs tasks as directed. The command-line interpreter, which is usually part of the operating system, is responsible for loading applications and directing the flow of information between them.

man section

A section, if provided, will direct man to look only in that section of the manual.

GNU

A set of tools for creating and managing open source software. Originally created to develop an open source Unix-like operating system.

Webmin

A web-based interface for system administration for Unix. Using any modern web browser, you can setup user accounts, Apache, DNS, file sharing and much more. It also removes the need to manually edit Unix configuration files like /etc/passwd, and lets you manage a system from the console or remotely.

built-in commands

Also known as, "internal command", are part of the shell itself. Each builtin command is executed directly in the shell itself, instead of an external programme which the bash would load and run. For example, the top is an external command, and an alias is an internal or builtin command.

- in front of a command e.g. uname --all

BSD style of entering an option with a command e.g. -- with the option spelled out

SUSE Linux Enterprise

Contains proprietary code and is sold as a server product

LibreOffice Impress

Create and edit slides

Canonical

Creators of Ubuntu. They also provide paid enterprise support.

Debian

Debian is more of a community effort, and as such, also promotes the use of open source software and adherence to standards. Debian came up with its own package management system based on the .deb file format.

LibreOffice Base

Desktop database

LibreOffice Draw

Diagramming software

nano /etc/apt/sources.list

Edit apt repositories

rpm -e

Erase or uninstall rpm package

/

Everything on your Linux system is located under the / directory, known as the root directory.

FHS

Filesystem Hierarchy Standard, A standard outlining the location of set files and directories on a Linux system

Audacity

Free and open-source audio editing tool

OpenShot

Free and open-source video editing tool

Chromium

Google's open-source browser

yum udpate

If run without any packages, update will update every currently installed package.

apt install {package name}

Install a package using apt. Use apt over apt-get when possible. apt is the newer version

yum install {package name}

Is used to install the latest version of a package or group of packages while ensuring that all dependencies are satisfied.

/dev

Linux exposes devices as files to this directory. Contains a number of special files that represent devices. But it's actually virtual items, that each one is representing a piece of hardware on your system

sources.list

List of configured APT data sources

Red Hat Certified Hardware

List of supported Linux hardware for Red Hat. https://access.redhat.com/ecosystem/search/#/category/Laptop

Ubuntu Certified Hardware

List of supported Linux hardware for Ubuntu. https://certification.ubuntu.com/

Firefox

Mozilla Corporation's browser usually the default browser in most Linux distros

Data flow of Linux command

One of the most important things to remember about these device files is that they are most definitely not device drivers. They are more accurately described as portals to the device drivers. Data is passed from an application or the operating system to the device file which then passes it to the device driver which then sends it to the physical device. The reverse data path is also used, from the physical device through the device driver, the device file, and then to an application or another device.

dmesg

Print kernel & driver messages

uname

Print system information. -a prints all system information. -o prints the operating system. -p prints the processor's architecture type.

dpkg -P

Purge an installed or already removed package. This removes everything, including conffiles, and anything else cleaned up from postrm. The OS usually caches the package and it will also remove it.

rpm -h

RPM options: display hash marks indicating progress

dnf

RPM packages will not install unless the prerequisites are installed first so YUM performed the dependency analysis and installed pre-requisites before installing the package. Fedora developed this package manager as a successor or next generation version of YUM.

Open Source

Refers to any software whose source code is made available free for any third party to review and modify. Not necessarily free

dpkg -r

Remove package. Most developers will include a script to remove all of their residual package files and directories

software repositories

Servers where free or open source software is available to be downloaded. Use to get latest updated versions of software instead of manually downloading the packages.

Commericial software

Software that is available for purchase.

Free software

Software that is free to run, copy, change or adapt, and share with friends, family or colleagues.

LibreOffice Calc

Spreadsheet program

xterm

Standard terminal window used by most Linux distros

Linux shell

The command line interpreter in Linux, is actually a program, /bin/bash is most common, fully functional scripting language with loops, conditionals, variables, function definition, and builtin functions,

Red Hat Linux

The largest commercial Linux distribution. Also has closed-source Linux Software.

Linux is file based

The majority of tasks you complete in Linux are linked to a file. Hardware is also linked to a file.

yum search {package name}

This is used to find packages when you know something about the package but aren't sure of it's name.

yum remove {package name}

Uninstall a package using yum.

apt purge {package name}

Uninstall the package using apt and remove its configuration files.

apt remove {package name}

Uninstall the package using apt, leaving behind its configuration files.

- in front of a command e.g. uname -a

Unix style of entering an option with a command e.g. dash with a single letter

sudo apt update

Updates the list of possible applications to install but does not install the updates

rpm -U

Upgrades or installs a new rpm package

rpm -qi

Uses the RPM database to provide package information (equivalent to yum info).

rpm -ivh

View verbose information of a rpm package installation with a progress bar

rpm -Uvh pkg.rpm

View verbose information of a rpm package upgrade with a progress bar

Linux Terminal

Where you run commands in a Linux System. Usually decided by which windows management system you are using.

LibreOffice Writer

Word processing software

/etc/yum.repos.d/webmin.repo

add .repo file to this directory to install and update packages (in this case webmin.repo) via yum

package

an archive, a collection of all the files that make up a program

man

an interface to the system reference manuals

apt vs dpkg

apt is better at managing your packages because it can also be used to get updates

cd

change directory

anaconda

code name for the Red Hat installer

alias

command that lists all command aliases

sudo dnf update

command to update CentOS v8+ packages using the dnf update manager.

apt-get

command-line tool for handling packages, can also look at a tool to determine what the dependencies are and install them as well. A newer tool is apt.

dd

command-line utility for Unix and Unix-like operating systems whose primary purpose is to convert and copy files also known as "disk dump"

cp

copy a file or directory

udev

daemon that runs in the background, manages the automatic detection and configuration of coldpluggable (during boot) and hotpluggable devices (during runtime)

echo

display a line of text

rpm -v

displays a verbose version of the installation.

LibreOffice

free and open-source office productivity software suite which acts as a replacement for Microsoft Office

wget https://prdownloads.sourceforge.net/webadmin/webmin_1.984_all.deb

free utility for non-interactive download of files from the Web. It supports HTTP, HTTPS, and FTP protocols, as well as retrieval through HTTP proxies. Non-interactive, meaning that it can work in the background, while the user is not logged on.

dpkg -I

gets information about the package file including installation prerequisites

Downtream linux changes

improvement to the kernel can be sent to the public made by the linux development team

Upstream linux changes

improvements to the kernel can be sent to the linux development team

dpkg -i

install .deb package file

rpm -i

installs a package. Use the entire package filename when installing.

yum

interactive, rpm based, package manager. It can automatically perform system updates, including dependency analysis and obsolete processing based on "repository" metadata.

Linux Kernel

is responsible for allocating the computer's resources and scheduling user jobs

ls

lists directory contents

which

locate a command

apt-key

manages the list of keys used by apt to authenticate packages. Packages that have been authenticated using these keys will be considered trusted.

dpkg

package manager for Debian

rpm

powerful Package Manager, which can be used to build, install, query, verify, update, and erase individual software packages. You can download rpm packages and transfer them to an air-gapped system.

uname -a

prints all system information.

uname -o

prints the operating system.

uname -p

prints the processor's architecture type.

apt

provides a high-level commandline interface for the package management system.

info

read info documents but differs from the man command because it is more of a rich text expericence e.g. the use of links through the use of its hypertext language

apt search

search can be used to search for the given regex(7) term(s) in the list of available packages and display matches.

grep

searches for PATTERNS in each FILE

man 5 passwd

see section 5 of the passwd file

.deb

tar archived compressed file

apt upgrade

to install available upgrades of all packages currently installed on the system from the sources configured via sources.list

apt update

used to download package information from all configured sources.

yum list {package name}*

used to list various information about available packages