• Update the packages

sudo apt-get update
sudo apt upgrade

• Install prerequisite packages (ZSH, powerline & powerline fonts)

sudo apt install zsh
sudo apt-get install powerline fonts-powerline

• Clone the Oh My Zsh Respo

git clone https://github.com/robbyrussell/oh-my-zsh.git ~/.oh-my-zsh

• Create a New ZSH configuration file

cp ~/.oh-my-zsh/templates/zshrc.zsh-template ~/.zshrc

• Set up a Fancy theme for your Terminal - Open .zshrc File using nano editor

nano .zshrc

• Find the line ZSH_THEME="robbyrussell" replace robbyrussell with agnoster theme in .zshrc File (CTRL + X & Enter to Save)

ZSH_THEME="agnoster"

• Change your Default Shell

chsh -s /bin/zsh

• Update & Uninstallation oh-my-zsh Visit - https://github.com/robbyrussell/oh-my-zsh#manual-updates

cd .oh-my-zsh
upgrade_oh_my_zsh

Want Syntax Highlighting? install ZSH Syntax Highlighting for Oh My Zsh

• Clone the ZSH Syntax Highlighting

git clone https://github.com/zsh-users/zsh-syntax-highlighting.git "$HOME/.zsh-syntax-highlighting" --depth 1

• Add syntax-highlighting in .zshrc Configuration

echo "source $HOME/.zsh-syntax-highlighting/zsh-syntax-highlighting.zsh" >> "$HOME/.zshrc"

Revert Back to Default Shell

chsh -s /bin/bash