Linux

Linux is a family of free and open-source software operating systems built around the Linux kernel. Typically, Linux is packaged in a form known as a Linux distribution for both desktop and server use.

Linux is a community of open-source Unix like operating systems that are based on the Linux Kernel. It was initially released by Linus Torvalds on September 17, 1991. It is a free and open-source operating system and the source code can be modified and distributed to anyone commercially or noncommercially under the GNU General Public License. Initially, Linux was created for personal computers and gradually it was used in other machines like servers, mainframe computers, supercomputers, etc. Nowadays, Linux is also used in embedded systems like routers, automation controls, televisions, digital video recorders, video game consoles, smartwatches, etc. The biggest success of Linux is Android(operating system) it is based on the Linux kernel that is running on smartphones and tablets. Due to android Linux has the largest installed base of all general-purpose operating systems. Linux is generally packaged in a Linux distribution.

inux distribution is an operating system that is made up of a collection of software based on Linux kernel or you can say distribution contains the Linux kernel and supporting libraries and software. And you can get Linux based operating system by downloading one of the Linux distributions and these distributions are available for different types of devices like embedded devices, personal computers, etc. Around 600 + Linux Distributions are available

What is Linux?

Just like Windows, iOS, and Mac OS, Linux is an operating system. In fact, one of the most popular platforms on the planet, Android, is powered by the Linux operating system. An operating system is software that manages all of the hardware resources associated with your desktop or laptop. To put it simply, the operating system manages the communication between your software and your hardware. Without the operating system (OS), the software wouldn’t function.

• Bootloader – The software that manages the boot process of your computer. For most users, this will simply be a splash screen that pops up and eventually goes away to boot into the operating system.
• Kernel – This is the one piece of the whole that is actually called ‘Linux’. The kernel is the core of the system and manages the CPU, memory, and peripheral devices. The kernel is the lowest level of the OS.
• Init system – This is a sub-system that bootstraps the user space and is charged with controlling daemons. One of the most widely used init systems is systemd, which also happens to be one of the most controversial. It is the init system that manages the boot process, once the initial booting is handed over from the bootloader (i.e., GRUB or GRand Unified Bootloader).
• Daemons – These are background services (printing, sound, scheduling, etc.) that either start up during boot or after you log into the desktop.
• Graphical server – This is the sub-system that displays the graphics on your monitor. It is commonly referred to as the X server or just X.

The following are explained while installing Linux or during the first boot-up

History

Distributions

Devices and Drives in Linux

Filesystem Hierarchy

Components: Kernel, Distribution, XFree86, Sawfish, Gnome.

User Software

GNOME Basics. Changing the desktop background, adding menu items, plugins.

Changing the screen resolution

Evolution - the default e-mail client in Fedora.

Mozilla - Web browser

OpenOffice - Productivity tools. Word processor, spreadsheet, presentation software.

gaim - Chat application

XScreensaver

How user preferences are stored in your home directory

Updating your system with up2date / yum.

How to restart X11: Ctrl-Alt-Backspace

The command-line

The command-line (shells, tab completion, cd, ls)

file management: cd, df, find, locate

nano, the text editor that replaces pico.

man pages - the help system

ssh - secure text-based connectivity to other machines. Demonstrate X-Forwarding.

Handling compressed archives with zip and tar.

GNU screen - The ability to resume command-line sessions from anywhere.

 Basic Administration

Adding users, groups

su - the obsoleted way to become the root user.

sudo - the modern way to run processes as another user.

Changing users passwords with the passwd command.

Printing with CUPS.

Installing new software with yum (if Fedora) or YaST (if SUSE)

Installing new software with rpm

Installing webmin for easy web based systems administration

System Administration

logfiles. Using tail -f to watch /var/log/messages

Configuring Kerberos authentication

Explaining file permissions, including setuid.

How to enable and disable services

ntp - Setting up time synchronization

Setting DNS settings by editing /etc/resolv.conf

Changing XFree86 settings in /etc/XFree86/XFree86.conf

Apache and MySQL administration

About the Apache webserver.

About the MySQL database engine.

About the PHP scripting language.

Enabling the Apache with PHP and MySQL services

Using MySQL Administrator

PHPMyAdmin - web based administration and query console for MySQL.

Adding a MySQL user in phpmyadmin

Installing WordPress- a popular blogging software that uses MySQL.

Installing Coppermine - a popular photo gallery software that uses MySQL.

Windows Integration

Connecting to your Linux machine from Windows using PuTTY and WinSCP.

WINE - free Windows API compatibility layer, for running Windows applications in Linux. We will use mIRC as a sample application.

Samba basics.

Configuring Samba to authenticate using ADS

rdesktop - Windows Terminal Server Client.

smbclient - an FTP-like client for SMB shares

smbmount - Mounting samba shares to a local directory (explain mount)

smb4k (unless Konqueror decides to work)

Automation

cut - cutting out the good parts of your input

sort - sorting files

uniq - finding the unique lines in a set of input

sed - searching and replacing, tail, head

find -exec - running a command on a large set of files

Writing a shell script

Scheduling tasks with cron.

System Administration II

Mounting disks

Killing processes with kill

Where to find software: freshmeat.net

Fetching files with wget

Compiling software: configure, make, make install

Reviewing find and du for finding out where your disk space went to.

Single user mode

X: Networking Tools

ping - check if a host is online

traceroute - see your hops between hosts

telnet - diagnostics

nmap - seeing what ports are open on a host

- the "internet super server". TCP/IP service manager.

lsof - list open ports and files

ethereal - Packet Sniffer Extraordinaire.

Final Test

For the final test, I will present a badly beaten Linux machine. It's got numerous problems on it, and they need to be fixed. Here are some problems you will run up against:

You don't know the root password. (Pay attention to how single user mode works, and how to change users passwords)

You don't know the MySQL root password, but need to get access to the database. You will need to use Google to research the answer to this one.

The settings in XFree86 are not right for the current monitor, so it is not starting up.

The /var partition is full.

Customizing your user environment

symbolic links

The Z Shell

aliases, including -s types in zsh.

variables

PATH

prompts

Terminal transparency

adding things to your X startup