What is apt get update install command | How apt-get works. 

apt stands for ‘Advanced Package Tool’, APT, is a free-software user interface that works with core libraries to handle the ‘installation, removal, search, update, upgrade’ any software package on Debian based operating system such as Ubuntu. 
apt-get helps us to install the packages on your system using apt-get and related commands. with the help of apt-get you can install any new package or remove already installed package, or update all installed packages to the latest versions.
Apt manages Package management via apt-get runs hand-in-hand with the “/etc/apt/sources.list” file. For information on editing or updating your sources list see. 
List of some popular frequently used command list we, We can install it simultaneously using install.sh script or choose any one particular package as per requirement. 

Script to install multiple packages on Ubuntu Linux

#!/bin/bash
sudo #apt-get update -y

sudo #apt-get install -y ispell

sudo #apt-get install -y pdftk

sudo #apt-get install -y gv
sudo #apt-get install -y djview
sudo #apt-get install -y openssh-server

sudo #apt-get install -y sshd
sudo #apt-get install -y texlive
sudo #apt-get install -y gfortran
sudo #apt-get install -y alpine
sudo #apt-get install -y vlc
sudo #apt-get install -y emacs
sudo #apt-get install -y gnuplot-qt
sudo #apt-get install -y latex-baemer
sudo #apt-get install -y kile
sudo #apt-get install -y konqueror
sudo #apt-get install -y xfig
sudo #apt-get install -y grace

sudo #aptitude install -y build-essential

sudo #apt-get install -y texlive-publishers
sudo #apt-get install -y openjdk-6-jre icedtea6-plugin
sudo #apt-get install -y ispell
sudo #apt-get install -y traceroute
sudo #apt-get install -y firefox 
sudo #apt-get install -y flashplugin-installer
sudo #apt-get install -y default-jre
sudo #apt-get install -y openjdk-7-jre
sudo #apt-get install -y oracle-java7-install
sudo #apt-get install -y oracle-java8-install
sudo #apt-get install -y gap