The Perfect Zsh Setup: Oh My Zsh on CachyOS/Arch

If you want a terminal that tells you if a command is valid, predicts what you’re about to type, and shows your Git branches, follow this clean-slate guide.

1. Install the Foundations

Before installing the framework, we need the "Holy Trinity" of Zsh plugins and a font that can handle icons.

# Install the core plugins and Git
sudo pacman -S zsh-syntax-highlighting zsh-autosuggestions git ttf-jetbrains-mono-nerd

2. Install Oh My Zsh

Run the official script to install the framework:

sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"

3. The "Master" Configuration (.zshrc)

This is the most important part. We need to tell Zsh to load the plugins from the system folders (where Arch installs them) and hook up Ruby.

Open your config: nano ~/.zshrc

Delete everything inside and paste this optimized block:

# 1. Path to Oh My Zsh
export ZSH="$HOME/.oh-my-zsh"

# 2. Theme (Agnoster is the best for Git branch visibility)
# Note: Requires a Nerd Font in terminal settings to see arrows/icons
ZSH_THEME="agnoster"

# 3. Core Plugins
plugins=(git ruby rbenv sudo archlinux)

# 4. Load Oh My Zsh
source $ZSH/oh-my-zsh.sh

# 5. Developer Tools (rbenv for Ruby)
export PATH="$HOME/.rbenv/bin:$PATH"
eval "$(rbenv init -)"

# 6. Pro Features (Syntax Highlighting & Autosuggestions)
# We source these manually to ensure they work perfectly on Arch/Cachy
source /usr/share/zsh/plugins/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh
source /usr/share/zsh/plugins/zsh-autosuggestions/zsh-autosuggestions.zsh

# 7. Helpful Aliases
alias yay='paru'
alias cls='clear'

4. Final Polish (Icons & Colors)

Fix the Icons

If you see squares instead of arrows/branches:

1. Open your Terminal (Konsole/Alacritty) Settings.
2. Go to Appearance -> Font.
3. Select JetBrainsMono Nerd Font.

Apply Changes

source ~/.zshrc

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Why this setup is better:

✅ Green/Red Syntax

Type ls - it turns green because the command exists.
Type asdf - it turns red because the command is invalid. No more "command not found" surprises.

✅ Inline Ghost Suggestions

As you type, you'll see a gray preview of your last used command. Just hit the Right Arrow key to complete it. It's like autocomplete for your terminal.

✅ Smart Git Branches

The moment you cd into a project folder, the prompt changes to show exactly which branch you are on and if you have uncommitted changes.

✅ rbenv Integration

Ruby versions are automatically handled. If you have a .ruby-version file in a project, the shell switches to it immediately.

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Pro-Tip for CachyOS Users:

CachyOS sometimes looks for your config in ~/.config/zsh/.zshrc. If your changes don't show up, run this to sync them:
mkdir -p ~/.config/zsh && cp ~/.zshrc ~/.config/zsh/.zshrc