Joseph O'Shea

Making your command line effective and enjoyable — Part 1: oh-my-zsh

zshclioh-my-zsh

Introduction

Why should I read this?

Do you find yourself occasionally using the command line during your work, but spend most of that time thinking "I wish I could be writing code"? Do you...

The goal of this article is to use a simple but powerful tool to make any time you spend on the command line:

  1. Less frustrating
  2. More intuitive
  3. More efficient

Without requiring any advanced knowledge of the command line or shell scripting. By using free tools, you get access to a lot of powerful functionality for very little effort.

Background

What is Zsh?

Zsh is a shell. You are probably familiar with Bash which is the default shell on most Linux distributions. On it's own Zsh does not provide huge advantages over Bash, but when combined with the community maintained oh-my-zsh it will significantly improve your command line experience. I have found it not only makes me more efficient, but it also makes my time spent on the command line far more enjoyable.

What is oh-my-zsh?

Oh My Zsh is an open source, community-driven framework for managing your zsh configuration.
source: oh-my-zsh readme

Essentially, it gives you a powerful Zsh configuration with very little work on your end.

Getting it set up

Install Zsh and oh-my-zsh

Install zsh, git, and curl

on Ubuntu 

sudo apt-get install zsh git curl

on MacOS: 

brew install zsh git curl

If you don't have brew installed, see (how to install homebrew)

Change default shell to zsh 

sudo chsh USERNAME -s /usr/bin/zsh

Install oh-my-zsh

(source)

git clone git://github.com/robbyrussell/oh-my-zsh.git ~/.oh-my-zsh
cp ~/.oh-my-zsh/templates/zshrc.zsh-template ~/.zshrc

Pick your plugins

A large part of the power of oh-my-zsh comes from plugins. Each plugin adds useful functionality to your shell for a particular program, language, or framework. There are plugins for git, python, heroku, docker, etc.

My recommendation is to start with only a few at first and then add more as you see fit. For me, the only plugin I always use is the git plugin.

You can see the list of available plugins in ~/.oh-my-zsh/plugins

To select your plugins:

  1. open your ~/.zshrc using your text editor of choice

    examples

    with nano

    nano ~/.zshrc

    with vscode:

    code ~/.zshrc

  2. find the line that looks like

    plugins=()

  3. you chose which plugins are loaded by placing them inside the () separated by spaces

    example - git:

    plugins=(git)

    example - git and python:

    plugins=(git python)

  4. after changing ~/.zshrc, you need to reload any open shells load the plugins by running:

    source ~/.zshrc

Disabling a plugin

If you ever want to disable a plugin, just remove it from the list and reload with

source ~/.zshrc

Pick your theme

Your oh-my-zsh theme determines the look & feel of your terminal. You could make your own theme if you wanted, but there are so many provided by the community that you will probably find one you like.

First, go here and find a theme you like. Don't overthink it - you can always change it very easily at any time. I prefer aussiegeek, but it is just personal preference so chose what fits you.

Once you have selected your theme, you have to activate it:

  1. To set your theme, open ~/.zshrc in your text editor

  2. near the top is a line like this

    ZSH_THEME="robbyrussell"

    replace robbyrussell with the name of the theme you want

    ZSH_THEME="aussiegeek"

  3. save your changes to ~/.zshrc and reload it with

    source ~/.zshrc

If you have problems with fonts in your theme, you might need to install powerline fonts. On Ubuntu, this is just sudo apt-get install fonts-powerline

Exploring the awesome

Prefix based command history

In Bash, you can cycle through your past commands with the up arrow. This is useful, but only if the command you need was one you used quite recently. This Zsh setup makes this feature much more powerful by providing command history that is filtered by prefix. For example, if you type sudo and then press the up arrow, you will cycle through all commands in your history which start with sudo.

In my opinion, this is the single most useful feature you get from using oh-my-zsh. It has saved me an incredible amount of time. Now that I have it, I can't imagine using the command line without it.

Useful general purpose aliases

oh-my-zsh provides a variety of useful aliases for common commands. These will save you a lot of typing. All of these can be changed, but I find the defaults to be quite nice. Some examples:

To see all the aliases available in your shell, run the alias command.

Plugins provide aliases to shorten common commands

Plugins also provide useful aliases for commonly used commands in popular tools. For example, the git plugin provides aliases such as:

Once you've activated a plugin you have all its aliases available to you.

Most plugins will provide a set of aliases to shorten common commands.

How do you find what they are? The alias command lists all available aliases, but this will be a very long list. You can read over that whole list if you'd like, but my recommendation is to use alias | grep 'git' to see all aliases containing git.

My advice is whenever you find yourself running any given command often (e.g., git commit) check to see if there is an alias for it and switch to using that.

While it is difficult to memorize a long list of aliases right away, I have found success in trying to learn 1-2 new aliases at a time. They will quickly become a natural part of your workflow. Within a few weeks the majority of your commands will be written using aliases and you'll be typing a lot less on the command line.

Conclusion

What was it all for? What did I gain from reading this?

This guide touches on a few of the most powerful features of oh-my-zsh for common development purposes. This is only the tip of the iceberg. The community behind oh-my-zsh has created a vast array of useful plugins and themes. No matter what language or framework you use, there are plugins for many of them from the common to the mundane. The litany of themes available means you will almost certainly find one that fits you.

By completing this guide, you have provided yourself with a significant power-up in your developer tool set for minimal time and effort. By using free tools built by the developer community, you have enhanced your command line with a handful of very powerful features that will make any amount of time you spend on the command line more enjoyable and efficient. The more time you spend on the command line, the more you will be grateful for these tools.

I hope you will find your time spent on the command line more effective and enjoyable now.

Appendix

Resources

A more detailed look at aliases

Aliases are quite helpful. They are simply a shorthand for another command. They take the following form:

alias slc="some_long_command"

If you had the above alias in your ~/.zshrc file, anytime you ran slc, it would be equivalent to running some_long_command.
For example: alias gd="git diff" - running gd will simply run git diff

Aliases also work with options: gcb='git checkout -b'

After you've internalized the most useful aliases provided by oh-my-zsh plugins, you may find yourself longing for new custom aliases to fit your needs. Fortunately it is extremely easy to make any alias you want. Simply follow the format above and place each alias on a separate line in your ~/.zshrc (don't forget to reload with source ~/.zshrc). Here are some examples from my ~/.zshrc:

alias shrug="echo '¯\_(ツ)_/¯'"
alias agrep="alias | grep"
alias lg="ll | grep"
alias lag="la | grep"
alias nrc="nano ~/.zshrc"
alias src="source ~/.zshrc"
alias genpwd="gpg --gen-random --armor 1 128"

alias vup="vagrant up"
alias vssh="vagrant ssh"
alias vhalt="vagrant halt"
alias vr="vagrant reload"
alias vrp="vagrant reload --provision"

Tip - avoid mistakes by using different themes in different environments

Have you ever had that moment where you thought your were running a command on your laptop, but after pressing ENTER you realized you were actually logged into your production server? If you haven't you're one of the lucky ones. Either way, there is a simple way to use oh-my-zsh themes to help prevent you from making this potentially costly mistake.

The idea is to use a different theme (optimally one that looks very different) on your servers from the one you use on your development machine. This means your local terminals will look distinct from your servers, and thus you will be more likely to notice with you are using.

There are other solutions to this as well, such as modifiying the status line to say "PRODUCTION" or something similar.