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The setup.sh script automates the complete setup of a macOS development environment. It handles everything from cloning configuration files to installing software packages.

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Overview

The setup script performs these tasks in order:
  1. Ensures the config repository is cloned to ~/.config
  2. Symlinks dotfiles from the config repo to your home directory
  3. Installs Xcode Command Line Tools if missing
  4. Enables Touch ID for sudo authentication
  5. Installs Homebrew if not present
  6. Runs brew bundle to install all packages from the Brewfile

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Script Configuration

The script uses these settings: 
set -eu  # Exit on error, treat unset variables as errors
Constants:
  • CONFIG_REPO_URL: https://github.com/mac9sb/config.git
  • CONFIG_DIR: $HOME/.config

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Utility Functions

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log()

Logs informational messages with timestamps. Location: setup.sh:4-7 Signature: 
log() {
  level="${2:-INFO}"
  printf "%s [%s] %s\n" "$(date +'%Y-%m-%dT%H:%M:%S%z')" "$level" "$1"
}
Parameters:
  • $1: Message to log
  • $2: Log level (default: “INFO”)
Output format: 2026-03-01T10:30:45-0800 [INFO] Starting macOS setup

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die()

Logs an error message and exits the script with status code 1. Location: setup.sh:9-12 Signature: 
die() {
  log "$*" "ERROR"
  exit 1
}
Parameters:
  • $*: Error message to log
Usage: Called when a fatal error occurs that prevents the script from continuing.

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warn()

Logs a warning message without stopping script execution. Location: setup.sh:14-16 Signature: 
warn() {
  log "$*" "WARN"
}
Parameters:
  • $*: Warning message to log
Usage: Used for non-fatal issues that should be brought to user attention.

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Core Functions

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ensure_config_repo()

Clones the config repository to ~/.config if not already present. Location: setup.sh:24-36 Behavior:
  • If ~/.config/.git exists, assumes repo is already present and returns
  • If ~/.config exists but is not a git repo, exits with error
  • Otherwise, clones the repository from GitHub
Error handling: Dies if ~/.config exists but is not a git repository. Creates symbolic links from dotfiles in ~/.config to the home directory. Location: setup.sh:39-49 Behavior:
  • Iterates through all hidden files (. prefix) in ~/.config
  • Skips ., .., and .git
  • Creates symlinks using ln -sf (force overwrites existing files)
Example: If ~/.config/.zshrc exists, creates ~/.zshrc pointing to it.

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install_xcode_clt()

Installs Xcode Command Line Tools if not already present. Location: setup.sh:52-62 Behavior:
  • Checks if CLT is installed using xcode-select -p
  • If missing, triggers the GUI installation prompt
  • Exits with status 0 and asks user to re-run after installation completes
Special note: This function exits the script if installation is needed, requiring the user to manually re-run setup.sh after the GUI installation finishes.

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enable_touchid_for_sudo()

Configures Touch ID authentication for sudo commands. Location: setup.sh:65-86 Behavior:
  • Checks for /etc/pam.d/sudo_local.template
  • If target file already has Touch ID enabled, skips
  • Copies template to /etc/pam.d/sudo_local
  • Uncomments the pam_tid.so line using sed
Requirements: Requires sudo privileges to modify /etc/pam.d/sudo_local. Error handling: If modification fails, logs a warning but continues execution.

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install_brew_if_missing()

Installs Homebrew if not already present on the system. Location: setup.sh:89-97 Behavior:
  • Checks if brew command is available
  • If missing, downloads and runs the official Homebrew installation script
Installation source: https://brew.sh/install

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brew_bundle()

Runs brew bundle to install all packages defined in the Brewfile. Location: setup.sh:100-111 Behavior:
  • Changes to $CONFIG_DIR directory
  • Verifies Brewfile exists
  • Sources Homebrew shell environment
  • Executes brew bundle to install all packages
Error handling: If Brewfile is missing, logs a warning and skips installation.

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Execution Flow

The main execution block (setup.sh:114-121) runs these functions in order: 
log "Starting macOS setup"
ensure_config_repo
symlink_home_dotfiles
install_xcode_clt
enable_touchid_for_sudo
install_brew_if_missing
brew_bundle
log "Done ✅"

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Error Handling Strategy

The script uses several error handling approaches:
  1. Fatal errors: Use die() to log and exit (e.g., wrong OS, conflicting paths)
  2. Non-fatal warnings: Use warn() for issues that don’t prevent continuation
  3. Early returns: Functions check if work is already done and return early
  4. Set flags: set -eu ensures the script exits on any command failure or undefined variable

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Platform Check

Before any operations, the script verifies it’s running on macOS: 
[ "$(uname -s)" = "Darwin" ] || die "This script is macOS-only."
This prevents accidental execution on Linux or other Unix systems.

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Logging Format

All log messages use ISO 8601 timestamp format with timezone: 
2026-03-01T10:30:45-0800 [INFO] Starting macOS setup
2026-03-01T10:30:46-0800 [WARN] Brewfile not found
2026-03-01T10:30:47-0800 [ERROR] This script is macOS-only.

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