Switching from bash to zsh

For someone who never learned “computers” in school, I’m actually pretty fond of the command line interface. I was one of those kids who was lucky enough to have a computer at home since before I was born. The first operating system I could remember using was MS-DOS. So it was very important to learn the command line so I could load and play games.

And that’s also why, more than twenty years later, I must have DOSBox installed in every machine I own. It’s an emulator that let’s you play all the DOS games that you grew up with.

Back to the topic at hand. As a web developer, using the terminal is part and parcel of my day. But other than installing iTerm2 and customising its colour scheme, I never really did anything more. I recently chanced upon this article by Mike Buss on optimising the terminal experience and decided to try it out as well.

What is shell?

Shell is simply a command line interface (CLI) that allows users to interact with the computer’s operating system. Most people are used to graphical user interfaces (GUI) like Windows or OSX. Personally, I think people shy away from the command line because of the Hollywood Hacking trope that associate typing commands with hard-core hacking. Well, pointy-clicky with a mouse is never as fast tappity-tap on a keyboard. Just saying.

Bash vs Zsh

Bash is the default shell on Linux and Mac OS X. Zsh is an interactive shell which incorporates a lot of useful features from other shells. In addition, there’s a bunch of things Zsh can do to make your terminal experience better. Enhanced auto-completions and globbing, spell correction, path replacement, the list goes on.

My migration experience

I was not a terminal power-user to begin with, so it was pretty easy for me to just move over from Bash to Zsh. I would think that people who have customised their Bash configurations to a T may probably take longer to move everything over properly.

List of applications installed

iTerm2
Homebrew (I use homebrew to manage all my Mac packages so it was already installed)
Prezto (It's a configuration framework for Zsh)
Python (Needed for Powerline so you can get cool glyphs in your terminal)
Vim (Needed for Powerline so you can get cool glyphs in your terminal)
Powerline

Install iTerm2. It’s your terminal on steroids. Just download the installer from the site and run it.
Install Prezto. It’s a configuration framework for Zsh. The following is from the official documentation:
- Launch Zsh:
```
zsh
```
- Clone the repository:
```
git clone --recursive https://github.com/sorin-ionescu/prezto.git "${ZDOTDIR:-$HOME}/.zprezto"
```
- Create a new Zsh configuration by copying the Zsh configuration files provided:
```
setopt EXTENDED_GLOB
for rcfile in "${ZDOTDIR:-$HOME}"/.zprezto/runcoms/^README.md(.N); do
  ln -s "$rcfile" "${ZDOTDIR:-$HOME}/.${rcfile:t}"
done
```
  If, like me, you never used Zsh before, you should not have any .z* files in your home directory and this step should proceed without a hitch. But if you do have any .z* files, you will see a message telling you that the files exist.
  
  If you’re already using Zsh, there will be prompts asking if you want to replace those files. I suggest backing up those files, then replacing them with the ones Prezto is trying to install.
- Set Zsh as your default shell:
```
chsh -s /bin/zsh
```
- Restart your terminal and you should see the default Prezto theme, chevrons and all

Configure your .zpreztorc file. You can enable additional modules to make Zsh even more awesome. This is my module configuration.

# Set the Prezto modules to load (browse modules).
# The order matters.
zstyle ':prezto:load' pmodule \
  'environment' \
  'terminal' \
  'editor' \
  'history' \
  'directory' \
  'spectrum' \
  'utility' \
  'ssh' \
  'completion' \
  'homebrew' \
  'osx' \
  'git' \
  'syntax-highlighting' \
  'history-substring-search' \
  'prompt'

The order is very important. According to Josh Symonds, prompt must come last, history-substring-search must come before it, and syntax-highlighting must come before that.

Set up your theme. Prezto comes with a number of really nice themes (I’m using Paradox right now) but you can always create your own. All the theme files are in the ~/.zprezto/modules/prompt/functions folder in the format prompt_THEMENAME_setup. To switch themes, just set it in the .zpreztorc file:
```
zstyle ':prezto:module:prompt' theme 'THEMENAME'
```
Install Powerline to get all the cool glyphs to show up. This requires a few more steps. I’m also assuming you already have Homebrew installed. These steps are referenced from Chu Yeow’s article:
- Install python with homebrew
```
brew install python
```
- Install vim with homebrew
```
brew install vim --env-std --override-system-vim
```
  You must install vim after python so that it’ll compile with homebrew’s python.
- Install powerline with pip
```
pip install https://github.com/Lokaltog/powerline/tarball/develop
```
  Powerline should get installed to /usr/local/lib/python2.7/site-packages/powerline.
- Open /usr/local/lib/python2.7/site-packages/powerline. You should see the files required for integration with zsh, vim, tmux, etc. in the bindings directory.
- Add Powerline to zsh by adding this to your .zshrc file.
```
source /usr/local/lib/python2.7/site-packages/powerline/bindings/zsh/powerline.zsh
```
- You need to use a patched font, or one that is compatible with Powerline, as the non-ASCII font for iTerm2. I’m using Input Mono. Here’s a list of patched fonts you can use. Go to the iTerm2 preferences, under Profiles, you will find the Text options where you can set your font of choice.
If you happen to encounter an a long string of errors with the last line showing ValueError: unknown locale: UTF-8, then you need to add the following to your .zshrc file:
```
export LC_ALL=en_US.UTF-8
export LANG=en_US.UTF-8
```
Move over your bash configurations from your .bash_profile and .bashrc files to your .zshrc file. Note: this was simple and straightforward for me because I didn’t have much in those files to begin with. Just a couple of aliases and paths.

And that’s it. We now have a levelled-up terminal for all our development needs. Happy coding!

Prezto setup

References

Workflow, Developer life