The manual way
1. Clone the repository:
git clone git://github.com/robbyrussell/oh-my-zsh.git ~/.oh-my-zsh
2. Optionally, backup your existing ~/.zshrc file:
cp ~/.zshrc ~/.zshrc.orig
3. Create a new Zsh config file by copying the Zsh template we’ve provided:
cp ~/.oh-my-zsh/templates/zshrc.zsh-template ~/.zshrc
4. Set Zsh as your default shell:
chsh -s /bin/zsh
5. Start or restart Zsh by opening a new command-line window.