Machine-Specific Configuration Management

Overview

Multi-Machine Support: Same dotfiles repo works across multiple machines using hostname detection and automatic config overrides.

Core principle: Detect hostname → auto-load local/{hostname}.el → apply machine-specific overrides

When to Use

Use this skill when:

•Setting up dotfiles on a new machine
•Creating machine-specific settings
•Debugging why config differs between machines
•Understanding which hostname config is active
•Separating work/home/personal configurations

Quick Reference

Task	How	Details
Check hostname	`(system-name)` in Emacs	Returns current hostname
Machine variable	`jf/machine-name`	Stores detected hostname
Config file	`emacs/local/{hostname}.el`	Auto-loaded during init
Create override	Create file, add setq/config	Restart Emacs to load

Configuration Pattern

Setup New Machine

•Check hostname: Eval (system-name) in Emacs
•Create file: emacs/local/{hostname}.el
•Add overrides (see examples below)
•Restart Emacs (changes load automatically)

Override Examples

elisp

;; emacs/local/Mac.home.el

;; Machine-specific org-roam dailies
(setq org-roam-dailies-directory "dailies/Mac.home/")

;; Local paths
(setq my-documents-path "/Users/jefffarr/Documents/")

;; Machine-specific keybindings
(global-set-key (kbd "C-c h") 'home-function)

;; Package config override
(use-package some-package
  :config
  (setq package-setting 'home-value))

Common Machine-Specific Settings

Category	Examples
Org-roam	`org-roam-dailies-directory`, org directories, capture templates
File Paths	Document roots, project workspaces, backup directories
Packages	Different configs for work/home, integrations, dev tools
Display	Monitor settings, font sizes, themes, window rules

Multi-Environment Strategy

Environment Types

•Work machines: Work org-roam, work packages
•Personal machines: Home directories, personal tools
•Cross-platform: Platform-specific paths/packages

Load Order

•Core modules (from jf/enabled-modules)
•All standard modules
•Machine config (automatic from local/{hostname}.el)

Debugging

Check current machine:

•Variable: C-h v jf/machine-name
•Returns: Current hostname

File not loading:

•Verify filename matches hostname exactly
•Check file exists in emacs/local/ directory
•Restart Emacs after creating file

Override not working:

•Machine configs load last (correct)
•Verify variable name is correct
•Check for typos in hostname

Common Mistakes

Mistake	Why Bad	Fix
Wrong hostname	File won't load	Use exact output of `(system-name)`
Too many overrides	Hard to maintain	Only override what's different
No documentation	Forget why override exists	Comment purpose of overrides
Secrets in file	Security risk	Keep credentials out of repo
Duplicating base config	Maintenance burden	Override minimally

Best Practices

•Minimal overrides: Only change what's actually different
•Document purpose: Comment why settings are machine-specific
•No secrets: Keep API keys and credentials out
•Logical grouping: Keep related overrides together
•Test isolation: Verify base config still works without overrides