> ## Documentation Index
> Fetch the complete documentation index at: https://notes.vvkhash.com/llms.txt
> Use this file to discover all available pages before exploring further.

# macOS Terminal and Shell Productivity for DevOps Engineers

> Level up your macOS terminal: Homebrew, Oh My Zsh, SSH key management, PATH config, iTerm2 tricks, and battle-tested DevOps aliases.

The macOS terminal is a first-class DevOps workstation — especially when you layer in Homebrew, a well-tuned Zsh config, and a handful of macOS-native commands that simply don't exist on Linux. This page collects the patterns and one-liners that make day-to-day infrastructure work faster and less error-prone.

***

## Homebrew Essentials

Homebrew is the de-facto package manager for macOS. Everything below assumes it is already installed; if not, bootstrap it with a single line.

<Steps>
  <Step title="Install Homebrew">
    ```bash theme={null}
    /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
    ```

    The installer guides you through Xcode Command Line Tools if they are missing. On Apple Silicon, Homebrew lands in `/opt/homebrew/` — remember to add it to your PATH (see [PATH Management](#path-management) below).
  </Step>

  <Step title="Install packages">
    ```bash theme={null}
    brew install <formula>          # CLI tool or library
    brew install --cask <cask>      # GUI application (e.g. iTerm2, Docker Desktop)
    ```
  </Step>

  <Step title="Keep everything up to date">
    <CodeGroup>
      ```bash Update formulae list theme={null}
      brew update
      ```

      ```bash Upgrade all installed packages theme={null}
      brew upgrade
      ```

      ```bash Upgrade a single package theme={null}
      brew upgrade <formula>
      ```
    </CodeGroup>
  </Step>

  <Step title="Diagnose problems">
    ```bash theme={null}
    brew doctor
    ```

    Run this any time something feels off — it checks for broken symlinks, outdated Xcode tools, conflicting PATH entries, and more, then suggests fixes.
  </Step>
</Steps>

<Tip>
  Clean up old versions and cached downloads periodically to reclaim disk space:

  ```bash theme={null}
  brew cleanup --prune=7   # Remove versions older than 7 days
  ```
</Tip>

***

## Oh My Zsh and Shell Customisation

macOS has shipped Zsh as the default shell since Catalina. Oh My Zsh turbo-charges it with plugin management, themes, and hundreds of community shortcuts.

<Steps>
  <Step title="Install Oh My Zsh">
    ```bash theme={null}
    sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"
    ```
  </Step>

  <Step title="Pick a theme">
    Open `~/.zshrc` and set your preferred theme. A reliable, information-dense
    choice for DevOps work:

    ```bash theme={null}
    ZSH_THEME="agnoster"   # shows git branch + exit code in prompt
    ```

    For a faster, no-font-dependency option:

    ```bash theme={null}
    ZSH_THEME="robbyrussell"
    ```
  </Step>

  <Step title="Enable useful plugins">
    ```bash theme={null}
    plugins=(git z docker kubectl terraform aws brew macos)
    ```

    Add this line (or edit the existing `plugins=(...)` block) in `~/.zshrc`, then reload:

    ```bash theme={null}
    source ~/.zshrc
    ```
  </Step>
</Steps>

<Note>
  The `z` plugin tracks your most-visited directories and lets you jump to them
  with `z <partial-name>` instead of typing full paths. It pays for itself
  within the first hour.
</Note>

***

## macOS-Specific Terminal Commands

These commands either don't exist on Linux or behave differently — they're worth knowing because they integrate tightly with macOS internals.

<Accordion title="open — launch anything from the terminal">
  `open` is the terminal equivalent of double-clicking in Finder.

  ```bash theme={null}
  open .                        # Open current directory in Finder
  open ~/Downloads              # Open a folder
  open -a "Visual Studio Code" .  # Open current dir in a specific app
  open https://example.com      # Open URL in default browser
  open -R ~/some/file.txt       # Reveal file in Finder (don't open it)
  ```
</Accordion>

<Accordion title="pbcopy / pbpaste — clipboard integration">
  Pipe anything into the system clipboard or back out again — invaluable for sharing command output without mouse gymnastics.

  ```bash theme={null}
  cat ~/.ssh/id_ed25519.pub | pbcopy    # Copy SSH public key to clipboard
  pbpaste > ~/Desktop/snippet.txt       # Dump clipboard contents to a file
  echo "hello" | pbcopy && pbpaste      # Quick round-trip test
  ```
</Accordion>

<Accordion title="say — text-to-speech notifications">
  Useful for alerting you when a long-running script finishes without requiring you to watch the terminal.

  ```bash theme={null}
  terraform apply && say "Terraform apply complete" || say "Terraform failed"
  sleep 3600 && say "One hour timer done"
  ```
</Accordion>

<Accordion title="caffeinate — prevent sleep during long jobs">
  Stops macOS from sleeping while a script runs. Pairs perfectly with large deploys or overnight syncs.

  ```bash theme={null}
  caffeinate -i make build           # Keep system awake for the duration
  caffeinate -t 7200                 # Stay awake for exactly 2 hours
  caffeinate -s ./backup-script.sh   # Prevent system sleep (not display sleep)
  ```
</Accordion>

<Accordion title="networksetup — manage network from the CLI">
  Control Wi-Fi, DNS, and proxies without touching System Settings — great for scripted environment switching.

  ```bash theme={null}
  networksetup -listallnetworkservices            # List interfaces
  networksetup -getdnsservers Wi-Fi               # Show current DNS servers
  networksetup -setdnsservers Wi-Fi 1.1.1.1 8.8.8.8  # Set custom DNS
  networksetup -setairportpower en0 off           # Turn Wi-Fi off
  networksetup -setairportpower en0 on            # Turn Wi-Fi on
  ```
</Accordion>

<Accordion title="diskutil — disk and volume management">
  ```bash theme={null}
  diskutil list                        # List all disks and partitions
  diskutil info /dev/disk0             # Detailed info on a disk
  diskutil eraseDisk APFS MyDisk /dev/disk2   # Format a disk (DESTRUCTIVE)
  diskutil unmountDisk /dev/disk2      # Unmount all volumes on a disk
  ```

  <Warning>
    `diskutil eraseDisk` is irreversible. Always double-check the device
    identifier with `diskutil list` before running destructive commands.
  </Warning>
</Accordion>

<Accordion title="defaults — read and write macOS preferences">
  Every macOS app stores its settings in a plist database that `defaults` exposes as a CLI.

  ```bash theme={null}
  # Show hidden files in Finder
  defaults write com.apple.finder AppleShowAllFiles true && killall Finder

  # Disable the Gatekeeper quarantine warning (use carefully)
  defaults write com.apple.LaunchServices LSQuarantine -bool false

  # Speed up Dock animation
  defaults write com.apple.dock autohide-delay -float 0 && killall Dock

  # Show full path in Finder title bar
  defaults write com.apple.finder _FXShowPosixPathInTitle -bool true && killall Finder

  # Read a value back
  defaults read com.apple.dock autohide-delay
  ```
</Accordion>

***

## SSH Key Management on macOS

macOS Keychain can store SSH key passphrases so you authenticate once per boot rather than per session.

<Steps>
  <Step title="Generate a new key">
    Ed25519 is the current recommended algorithm — smaller and faster than RSA.

    ```bash theme={null}
    ssh-keygen -t ed25519 -C "your@email.com" -f ~/.ssh/id_ed25519
    ```

    For legacy servers that don't support Ed25519:

    ```bash theme={null}
    ssh-keygen -t rsa -b 4096 -C "your@email.com" -f ~/.ssh/id_rsa
    ```
  </Step>

  <Step title="Add the key to the agent with Keychain">
    The `--apple-use-keychain` flag (macOS-only) stores the passphrase in
    Keychain so you're only prompted once per machine restart.

    ```bash theme={null}
    ssh-add --apple-use-keychain ~/.ssh/id_ed25519
    ```
  </Step>

  <Step title="Persist across reboots via ~/.ssh/config">
    Add the following block so the agent reloads keys automatically on login:

    ```
    Host *
      AddKeysToAgent yes
      UseKeychain yes
      IdentityFile ~/.ssh/id_ed25519
    ```
  </Step>

  <Step title="Copy the public key to a remote host">
    ```bash theme={null}
    ssh-copy-id -i ~/.ssh/id_ed25519.pub user@remote-host
    # or, if ssh-copy-id is unavailable:
    cat ~/.ssh/id_ed25519.pub | pbcopy   # then paste into ~/.ssh/authorized_keys
    ```
  </Step>

  <Step title="List keys currently loaded in the agent">
    ```bash theme={null}
    ssh-add -l
    ```
  </Step>
</Steps>

<Tip>
  Use separate key pairs for different contexts — personal GitHub, work GitLab,
  cloud jump hosts — and route them with `Host` blocks in `~/.ssh/config`.
  This limits blast radius if a key is ever compromised.
</Tip>

***

## iTerm2 Tips

iTerm2 is the standard terminal emulator for macOS power users. A few features that pay dividends immediately:

| Feature                      | How to access                                                                     |
| ---------------------------- | --------------------------------------------------------------------------------- |
| Split panes                  | `⌘ D` (vertical) / `⌘ Shift D` (horizontal)                                       |
| Broadcast input to all panes | `⌘ Shift I` — type once, run everywhere                                           |
| Instant Replay               | `⌘ Opt B` — rewind terminal output by seconds                                     |
| Tmux integration             | `tmux -CC` — iTerm2 maps tmux sessions to native windows/tabs                     |
| Shell integration            | **iTerm2 → Install Shell Integration** — adds `imgcat`, marks, and jump-to-prompt |
| Profiles                     | Store different color schemes + working dirs per project                          |

<CodeGroup>
  ```bash Install via Homebrew theme={null}
  brew install --cask iterm2
  ```

  ```bash Install imgcat (display images in terminal) theme={null}
  brew install imgcat
  imgcat screenshot.png
  ```
</CodeGroup>

***

## PATH Management

On Apple Silicon, Homebrew lives at `/opt/homebrew/bin`, not `/usr/local/bin`. Managing PATH cleanly avoids subtle version conflicts between system tools and Homebrew-installed ones.

<Note>
  Use `~/.zprofile` for environment variables (runs at login) and `~/.zshrc`
  for interactive settings like aliases and plugins (runs per shell session).
  Avoid duplicating PATH exports across both files.
</Note>

```bash title="~/.zprofile — canonical place for PATH on Apple Silicon" theme={null}
# Homebrew (Apple Silicon)
eval "$(/opt/homebrew/bin/brew shellenv)"

# Homebrew (Intel fallback)
# eval "$(/usr/local/bin/brew shellenv)"

# Language version managers
export PATH="$HOME/.rbenv/shims:$PATH"         # Ruby
export PATH="$HOME/.pyenv/shims:$PATH"         # Python
export PATH="$HOME/go/bin:$PATH"               # Go binaries
export PATH="$HOME/.cargo/bin:$PATH"           # Rust

# Local scripts — highest priority
export PATH="$HOME/.local/bin:$PATH"
```

Check the effective PATH without opening a new shell:

```bash theme={null}
echo $PATH | tr ':' '\n'   # One entry per line — much easier to read
```

***

## DevOps Aliases

Drop these into `~/.zshrc` (or a sourced `~/.zsh_aliases` file). Reload with `source ~/.zshrc`.

```bash title="~/.zshrc — DevOps alias block" theme={null}
# ── Navigation ────────────────────────────────────────────────────
alias ..='cd ..'
alias ...='cd ../..'
alias ll='ls -lAhF'
alias llt='ls -lAhFt'          # sort by modified time

# ── Git ───────────────────────────────────────────────────────────
alias gs='git status -sb'
alias gp='git push'
alias gl='git pull --rebase'
alias glog='git log --oneline --graph --decorate --all'
alias gdiff='git diff --stat'

# ── Docker ────────────────────────────────────────────────────────
alias dk='docker'
alias dkps='docker ps --format "table {{.Names}}\t{{.Status}}\t{{.Ports}}"'
alias dkclean='docker system prune -af --volumes'
alias dklogs='docker logs -f --tail 100'

# ── Kubernetes ────────────────────────────────────────────────────
alias k='kubectl'
alias kgp='kubectl get pods -o wide'
alias kgs='kubectl get svc'
alias kgn='kubectl get nodes -o wide'
alias kctx='kubectl config current-context'
alias kns='kubectl config set-context --current --namespace'

# ── Terraform ─────────────────────────────────────────────────────
alias tf='terraform'
alias tfi='terraform init -upgrade'
alias tfp='terraform plan -out=tfplan'
alias tfa='terraform apply tfplan'
alias tfd='terraform destroy'

# ── macOS utilities ───────────────────────────────────────────────
alias flushdns='sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder'
alias showfiles='defaults write com.apple.finder AppleShowAllFiles true && killall Finder'
alias hidefiles='defaults write com.apple.finder AppleShowAllFiles false && killall Finder'
alias myip='curl -s https://ifconfig.me'
alias localip="ipconfig getifaddr en0"
alias brewup='brew update && brew upgrade && brew cleanup'
```

***

## Related Pages

<CardGroup cols={2}>
  <Card title="macOS Tips" icon="apple" href="macos/tips">
    Installing specific macOS versions, flushing DNS, customising the Dock,
    Spotlight tricks, and screenshot shortcuts.
  </Card>

  <Card title="Linux Bash Scripting" icon="code" href="linux/bash-scripting">
    Bash scripting patterns that work across macOS and Linux CI environments.
  </Card>

  <Card title="DevOps: Docker" icon="docker" href="devops/docker">
    Container workflows that build on the Docker aliases and CLI habits
    covered here.
  </Card>

  <Card title="DevOps: Kubernetes" icon="dharmachakra" href="devops/kubernetes">
    Kubectl patterns and cluster management techniques for your daily
    Kubernetes work.
  </Card>
</CardGroup>