Linux Shell Jumpstart!

Linux Introduction

Originally released by Linus Torvalds in 1991

UNIX -> MINIX -> LINUX

Free open source under GNU General Public License

Many tools from the GNU Project come packaged with Linux.
  This is often referred to as "GNU-Linux".

Distro: (meaning distributions)
  specific group of software and conventions.

Major distributions (distros): Arch, Debian, Red Hat, Slackware

Linux Mint, Ubuntu, kali, are derived from Debian

CentOS, Fedora, are derived from Red Hat

Bash shell is available on most distros and OSes.

Be aware of what system you're using and
  adapt to account for differences in distributions.

How to setup

Cygwin

Windows 10 has subsystem for Linux,
  which provides a bash shell environment.
  It runs within Windows instead of in a VM.

• How to Install Window 10 Bash Shell Command Line

Using a Virtual Machine

• Virtualbox.org from Oracle
• Ubuntu.com - Download Ubuntu Desktop

macOS is derived from BSD/UNIX, not from Linux

• macOS has similar but not the same tool chains.
• macOS includes the Bash shell.
• Go to applications and open up a terminal. There you go.

Using a Cloud Provider

Azure, AWS, GCP, DigitalOcean, Linode and more.

Ubuntu/Debian available instance for low tier.

Record the provided username and password/key for security login
  and SSH connection.

connect: ssh username@11.22.33.44

Early Windows system may not have SSH,
  download PuTTY to connect to the cloud server using SSH.
  PuTTY.org

Download files from GitHub

# open property by clocking top left logo, to select font size
#
# To run a command as administrator (uer "root"), use "sudo ".
% man sudo_root
# ctrl+shift+[+] # to enlarge
% sudo apt install git ## to use git
% git clone git://github.com/path/to/files

Command-Line basics

CLI: command line interface

CLI sends typed commands to OS

CLI display text output

The environment we use is called "shell" or "interpreter.

Early Thompson shell for UNIX in 1971

Bash: Bourne-again shell

General command Syntax:
  % Command Options Arguments

% ls -aFl /mnt/c/Users/username/Desktop
% grep "findthis" file.in

General Commands

% cd
% pwd
% man cd
% which ls
% find . -name "*in"
% grep pattern file.txt
% sort -u file.txt
% echo text
% export PATH=.:$PATH
% man nano
% which nedit
% which kate

login shell and profile

When bash is invoked as an interactive login shell, or as a non-interactive shell with the --login option, it first reads and executes commands from the file /etc/profile, if that file exists. After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order, and reads and executes commands from the first one that exists and is readable. The --noprofile option may be used when the shell is started to inhibit this behavior. When an interactive shell that is not a login shell is started, bash reads and executes commands from /etc/bash.bashrc and ~/.bashrc, if these files exist. This may be inhibited by using the --norc option. The --rcfile file option will force bash to read and execute commands from file instead of /etc/bash.bashrc and ~/.bashrc. In general .profile - for things not related to Bash, like environment variables PATH .bashrc - for configuring the interactive Bash usage like aliases, editor and prompt

% export VISUAL=vim
% export EDITOR="$VISUAL"
% export PS1="\u@\h\\$ "
% export PS1="[\w] \!> "
% export PS1="\u@\[\e[31m\]\h\[\e[m\] "

.bash_profile - for make sure .profile and .bashrc are loaded for login shells - If .bash_profile is omitted, only .profile would be loaded.

% . ~/.profile
% . ~/.bashrc