Multi-Device Config

TIP

If you only use rootbeer on a single machine, you can skip this page entirely.

One config repo, multiple machines. Rootbeer gives you three tools for profile-dependent config, from lightweight inline switches to full per-machine files. Mix and match as needed.

profile.select — Pick a Value

The most common case: one field differs between profiles. select returns the value matching the active profile, falling back to default when the profile isn't listed.

local profile = require("rootbeer.profile")
local git = require("rootbeer.git")

git.config({
    user = {
        name = "Aarnav Tale",
        email = profile.select({
            default = "aarnav@personal.me",
            work = "aarnav@company.com",
        }),
    },
    editor = "nvim",
})

Works anywhere a value is expected — strings, tables, lists:

local brew = require("rootbeer.brew")

local extra_casks = profile.select({
    personal = { "discord", "steam", "signal" },
    work = { "linear-linear", "notion", "slack" },
})

If the active profile has no entry and no default is set, select errors with a clear message listing the known keys.

profile.when — Conditional Blocks

For entire sections that only apply to certain profiles. Accepts a single name or a list.

local profile = require("rootbeer.profile")
local mac = require("rootbeer.mac")

profile.when("personal", function()
    mac.hostname({ name = "Aarnavs-MBP" })
    mac.touch_id_sudo()
end)

profile.when({"work", "personal"}, function()
    -- runs for either profile
    mac.dock({ autohide = true })
end)

When rb.profile is nil (no profile specified), when is a no-op.

profile.config — Separate Files

When differences are large enough that inline switches get unwieldy, split into dedicated files. This is the same model as NixOS flakes — each profile gets its own entrypoint.

-- rootbeer.lua
local profile = require("rootbeer.profile")

profile.config({
    work = "hosts/work.lua",
    personal = "hosts/personal.lua",
})

Each host file is a regular Lua script:

-- hosts/work.lua
local git = require("rootbeer.git")

git.config({
    user = {
        name = "Aarnav Tale",
        email = "aarnav@company.com",
    },
})

rb apply work        # runs hosts/work.lua
rb apply personal    # runs hosts/personal.lua

All paths are validated before the selected profile runs. If any referenced file is missing, you get an error immediately — even if that profile wasn't selected.

Combining Approaches

A typical setup uses all three together — select for individual values, when for conditional blocks, and config for large profile-specific overrides at the end:

local rb = require("rootbeer")
local profile = require("rootbeer.profile")
local git = require("rootbeer.git")
local brew = require("rootbeer.brew")
local mac = require("rootbeer.mac")

-- Shared config with inline value switches
git.config({
    user = {
        name = "Aarnav Tale",
        email = profile.select({
            default = "aarnav@personal.me",
            work = "aarnav@company.com",
        }),
    },
})

-- Entire block only for personal machines
profile.when("personal", function()
    mac.touch_id_sudo()
    mac.hostname({ name = "Aarnavs-MBP" })
end)

-- Heavy per-machine overrides in separate files
profile.config({
    work = "hosts/work.lua",
    personal = "hosts/personal.lua",
})

Host Detection

For differences that don't map to profiles (OS, architecture), branch on rb.host:

local rb = require("rootbeer")

if rb.host.os == "macos" then
    -- macOS-only config
end

See the Host reference for all available fields.

API Reference

config(map)

Selects and requires a module based on the active profile. Each key in the map is a profile name and its value is a path to a .lua file relative to the script directory. All paths are validated upfront before the selected profile is executed. When rb.profile is nil the call is a no-op. lua local profile = require("rootbeer.profile") profile.config({ work = "hosts/work.lua", personal = "hosts/personal.lua", })

maptable<string, string>

Profile name → .lua file path.

select(map)

Returns the value from map that matches the active profile. If the active profile is not in map, falls back to map.default. Errors when the profile has no matching entry and no default is set. When rb.profile is nil, returns the default value or errors. lua local profile = require("rootbeer.profile") local email = profile.select({ default = "aarnav@personal.me", work = "aarnav@company.com", })

maptable<string, any>

Profile name → value. Use "default" as the fallback key.

any

when(names, fn)

Runs fn only when the active profile matches. Accepts a single profile name or a list of names. When rb.profile is nil the call is a no-op. lua local profile = require("rootbeer.profile") profile.when("personal", function() mac.touch_id_sudo() mac.hostname({ name = "Aarnavs-MBP" }) end) profile.when({"work", "personal"}, function() -- runs for either profile end)

namesstring|string[]

One or more profile names.

fnfun()

The function to execute if the profile matches.