The Debian Project is an association of individuals who have made common cause to create a free operating system. This operating system that we have created is called Debian.

Debian systems currently use the Linux kernel or the FreeBSD kernel. Linux is a piece of software started by Linus Torvalds and supported by thousands of programmers worldwide. FreeBSD is an operating system including a kernel and other software.

Base of numerous distributions.

Ubuntu is an open source software platform that runs from the cloud, to the smartphone, to all your things

Target platforms

Based on Debian

My personal favorite at the moment.

Red Hat Enterprise Linux delivers military-grade security, 99.999% uptime, support for business-critical workloads, and so much more. Ultimately, the platform helps you reallocate resources from maintaining the status quo to tackling new challenges. It's just 1 reason why more than 90% of Fortune Global 500 companies use Red Hat products and solutions.

Variations: Enterprise, CentOS & Fedora Linux

The purpose of Linux Mint is to produce a modern, elegant and comfortable operating system which is both powerful and easy to use.

Based on Ubuntu and thus Debian

Raspbian

Debian variant designed for Raspberry Pi

Small in size (8Gb), runs off Micro SD card.

Android

Android is a mobile operating system based on a modified version of the Linux kernel and other open source software, designed primarily for touchscreen mobile devices such as smartphones and tablets

Mac OS X???

Mac OS X has origins in BSD

Not Linux by definition, but is a Unix variant

By default, the terminal in OS X is Bash or ZSH (z shell) so commands work just like Linux

Graphical Desktop Environments

GNOME 3

KDE (Plasma)

Unity (Ubuntu)

Cinnamon (Linux Mint)

Xfce

The Shell

or as you probably know it better as...

Terminal

Bourne Shell (sh)

This is the oldest shell and as such is not as feature rich as many of the other shells.

Bash Shell (bash)

The Bash shell is a combination of features from the Bourne Shell and the C Shell. It's name comes from the Bourne Again SHell. It has a command-line editor that allows the use of the cursor keys in a more "user friendly" manner than the Korn shell. It also has a useful help facility allowing you to get a list of commands by typing the first few letters followed by the "TAB" key. It is the default shell on most Linux distributions.

Z Shell (zsh)

ZSH, also called the Z shell, is an extended version of the Bourne Shell (sh), with plenty of new features, and support for plugins and themes. Since it’s based on the same shell as Bash, ZSH has many of the same features, and switching over is a breeze.

man

Outputs manual aka "man" page that explains how to use the specified command

man <command>

Uses VI navigation and exit commands (To be explained later)

Tab Completion

bash and z shell both support tab completion at the command line

{partial command, file name, directory name}[tab]

Type a string that makes up the beginning of a command, file name and directory name and press the tab key to complete the exact match.

{partial command, file name, directory name}[tab][tab]

If there is no exact match, no results will show, but doing it twice [tab][tab] to get a list of possible matches.

ls

List file & directories (DOS equivalent is dir)

* is the wildcard

ls -l

List files and directory long format and show permissions

ls -a

List files and directory including hidden files

ls -h

List files and directory using human readable file size

ls -lah

Combining them all together

mkdir

Create a new directory

mkdir {directory name}

Path Aliases

cd & pwd

Change directory

cd {path to any directory}

cd ..

(double period) Change to the parent directory

cd ~

(tilde) Change to your home directory

cd -

(dash) Change to previous directory

pwd

Output your current location

touch

Create a new file

touch {file name}

cp

Copy

cp {source} {destination}

Copy a file, destination default is the current directory & can be omitted.

cp -R {source} {destination}

Copy recursively including directories

Destination default is the current directory (.) & can be omitted.

rm

Remove

rm -R

Remove recursively

rm -f

Remove forcefully i.e.: don't ask if this is what I really mean!

Linux Shell does NOT have a recycle bin! ... Be warned, there is no turning back.

rm -Rf

Remove recursively and forcefully.... Again be warned!

history

Command History, lists commands executed recently

Use the !## (Bang aka Exclamation Point) to execute a previous command

Up and down arrow keys can be used to navigate previous commands as well

ctrl+r

Search command history, right on the command line

Press ctrl + r and type a search string, press enter key to accept

Example: `npm`

grep

Search a file for a given pattern or regex

grep <patttern/regex> <file(s)>

• There are various wildcards that can be used including the standard asterick *
• Regex can be used as well. Sorry that is a whole other talk.
  Additional Information: https://en.wikipedia.org/wiki/Regular_expression

cat

Outputs the contents of a file to the terminal

cat <file(s)>

<command> | <command>..

(pipe, pass-through)

You can pipe as many times as you like as long as the commands output to standard out.

Spaces around the pipe (|) are not required, but I personally feel it is more readable.

less is more

(pagination)

<command> | less

Less uses VI navigation and search functionality, space to advance full pages.

<command> | more

More is older and has less (not Less) functionality

More is found in most minimal distros due to its smaller size of 2000 lines vs less's 27000 lines.

chown

Change the ownership of a file or directory

chmod

Change the permissions of a file or directory

Permissions, you ask?

777, 664... It is complicated, read this: Permissions Calculator Info

top

Task Manager

htop

Human readable task manager

shutdown

Shuts down or restartt the computer gracefully after a given time period.

shutdown -h now

Shuts down (halts) the computer now

shutdown -r now

Restarts the computer now

shutdown -r 01:00 "The system will reboot at 1 AM"

Restarts the computer at 1:00 AM sending the message to all logged in users via terminal.

At 12:55 AM all new log in attempts will be blocked until after the reboot.

shutdown -c

Cancels a pending shutdown

.bashrc | .zshrc

.profile | .bash_profile | .zprofile

dot files

Dotfiles are used to customize your system. The “dotfiles” name is derived from the configuration files in Unix-like systems that start with a dot (e.g. .bash_profile and .gitconfig)

Getting Started With Dotfiles

Elevating Privileges/Becoming root

sudo <command>

Some actions require elevated privileges, this requires becoming root temporarily

sudo !!

Run the previous command with elevated rights

sudo su -

Becoming root for the duration of the session
This will give you elevated privileges for the entirety of the session

whoami

Find out what user account you are currently logged in to the shell using

exit

Exit the current user account

Editors

Nano

Vim (VI)

Nano

GNU nano is a text editor for Unix-like computing systems or operating environments using a command line interface. It emulates the Pico text editor, part of the Pine email client, and also provides additional functionality.

There is only 1 mode in Nano, Edit.

Commands are executed using Ctrl (^) + Letter combinations i.e.: ^x to exit.

Vim

Linux: http://www.vim.org/

Mac: http://macvim-dev.github.io/macvim/

Happy Birthday - Nov. 2, 1991

Why is Vim important?

Vim is found on EVERY linux computer and is available via the command line.

VI vs Vim

Vim includes most all basic features from VI. For this Intro they can be interchanged.

Vim also has numerous additional features inlcuding:

• Vim has been ported to a much wider range of OS's than vi.
• Vim includes support (syntax highlighting, code folding, etc) for several popular programming languages (C/C++, Python, Perl, shell, etc).
• Vim integrates with cscope.
• Vim can be used to edit files using network protocols like SSH and HTTP.
• Vim includes multilevel undo/redo.
• Vim allows the screen to be split for editing multiple files.
• Vim can edit files inside a compressed archive (gzip, zip, tar, etc).
• Vim includes a built in diff for comparing files (vimdiff).
• Vim includes support for plugins, and finer control over config and startup files.
• Vim can be scripted with vimscript, or with an external scripting language (e.g. python, perl, shell).

Open a file with VIM

vim {file name}

This will open the file in command mode. What is command mode?

Modes

Command (esc)

Enter commands such as goto line, search, find and replace

Insert (i,I,a,A,o,O)

Insert new characters, Append new characters, Open a new line and then insert characters

Replace (R)

Enter insert mode while replacing characters instead of "pushing them"

Vim Editor Modes Explained

Basic Editing

Basic Command Structure

<quantity>command<movement>

All commands are cASe SeNsiTive

Movement

By default Vim uses only the basic keyboard so moving the cursor is down with...

h j k l

Arrow Keys also work most of the time, which I prefer.

Visual Mode

There are 3 types of visual mode, character, line & block

We are just scratching the surface of visual mode, more details here: http://vimdoc.sourceforge.net/htmldoc/visual.html

Search

/{search}

"n" & "N" will take you to next (n) and previous (N) search string.

Search and Replace

aka: substitute

:s/{search}/{replace}/g

Search and replace with the "g" option will not ask for confirmation.

The exclamation point (!)

With that being said...

Has anyone ever been trapped in Vim?