Machine-Specific Configurations

chezmoi excels at managing dotfiles across multiple machines with different operating systems, hardware configurations, and purposes (work vs. personal, laptop vs. desktop, etc.). This guide covers techniques for handling machine-to-machine differences.

Detecting Machine Characteristics

Determine Laptop vs. Desktop

You can automatically detect whether a machine is a laptop or desktop and adjust configurations accordingly.

.chezmoi.toml.tmpl

{{- $chassisType := "desktop" }}
{{- if eq .chezmoi.os "darwin" }}
{{-   if contains "MacBook" (output "system_profiler" "SPHardwareDataType") }}
{{-     $chassisType = "laptop" }}
{{-   else }}
{{-     $chassisType = "desktop" }}
{{-   end }}
{{- else if eq .chezmoi.os "linux" }}
{{-   $chassisType = (output "hostnamectl" "--json=short" | mustFromJson).Chassis }}
{{- else if eq .chezmoi.os "windows" }}
{{-   $chassisType = (output "pwsh.exe" "-NoProfile" "-NonInteractive" "-Command" "if ((Get-CimInstance -Class Win32_Battery | Measure-Object).Count -gt 0) { Write-Output 'laptop' } else { Write-Output 'desktop' }") | trim }}
{{- end }}

[data]
    chassisType = {{ $chassisType | quote }}

Use in templates:

dot_bashrc.tmpl

{{- if eq .chassisType "laptop" }}
# Laptop-specific settings
export POWERSAVE=1
{{- else }}
# Desktop-specific settings
export POWERSAVE=0
{{- end }}

Detect CPU Cores and Threads

Optimize configurations based on available CPU resources:

.chezmoi.toml.tmpl

{{- $cpuCores := 1 }}
{{- $cpuThreads := 1 }}
{{- if eq .chezmoi.os "darwin" }}
{{-   $cpuCores = (output "sysctl" "-n" "hw.physicalcpu_max") | trim | atoi }}
{{-   $cpuThreads = (output "sysctl" "-n" "hw.logicalcpu_max") | trim | atoi }}
{{- else if eq .chezmoi.os "linux" }}
{{-   $cpuCores = (output "sh" "-c" "lscpu --online --parse | grep --invert-match '^#' | sort --field-separator=',' --key='2,4' --unique | wc --lines") | trim | atoi }}
{{-   $cpuThreads = (output "sh" "-c" "lscpu --online --parse | grep --invert-match '^#' | wc --lines") | trim | atoi }}
{{- else if eq .chezmoi.os "windows" }}
{{-   $cpuCores = (output "pwsh.exe" "-NoProfile" "-NonInteractive" "-Command" "(Get-CimInstance -ClassName 'Win32_Processor').NumberOfCores") | trim | atoi }}
{{-   $cpuThreads = (output "pwsh.exe" "-NoProfile" "-NonInteractive" "-Command" "(Get-CimInstance -ClassName 'Win32_Processor').NumberOfLogicalProcessors") | trim | atoi }}
{{- end }}

[data.cpu]
    cores = {{ $cpuCores }}
    threads = {{ $cpuThreads }}

Use in build configurations:

dot_config/make/settings.mk.tmpl

# Makefile settings
MAKEFLAGS += -j{{ .cpu.threads }}

Operating System Conditionals

Basic OS Detection

Use the .chezmoi.os variable to handle different operating systems:

dot_bashrc.tmpl

{{- if eq .chezmoi.os "darwin" }}
# macOS-specific settings
export HOMEBREW_PREFIX="/opt/homebrew"
alias ls='ls -G'
{{- else if eq .chezmoi.os "linux" }}
# Linux-specific settings
alias ls='ls --color=auto'
{{- else if eq .chezmoi.os "windows" }}
# Windows-specific settings
alias ls='ls --color=auto'
{{- end }}

Linux Distribution Detection

Handle differences between Linux distributions:

.chezmoi.toml.tmpl

{{- $osid := .chezmoi.os -}}
{{- if hasKey .chezmoi.osRelease "id" -}}
{{-   $osid = printf "%s-%s" .chezmoi.os .chezmoi.osRelease.id -}}
{{- end -}}

[data]
    osid = {{ $osid | quote }}

Use in scripts:

run_once_install_packages.sh.tmpl

#!/bin/bash

{{- if eq .osid "darwin" }}
brew install git vim curl
{{- else if eq .osid "linux-ubuntu" }}
sudo apt update
sudo apt install -y git vim curl
{{- else if eq .osid "linux-fedora" }}
sudo dnf install -y git vim curl
{{- else if eq .osid "linux-arch" }}
sudo pacman -S --noconfirm git vim curl
{{- end }}

Platform-Specific Guides

macOS

Use Homebrew Bundle

Manage packages declaratively with a run_onchange_ script:

run_onchange_before_install-packages-darwin.sh.tmpl

{{- if eq .chezmoi.os "darwin" -}}
#!/bin/bash

brew bundle --file=/dev/stdin <<EOF
brew "git"
brew "vim"
brew "tmux"
cask "visual-studio-code"
cask "iterm2"
EOF
{{ end -}}

Get Stable Hostname

The hostname command can change based on network. Use scutil instead:

{{- $computerName := output "scutil" "--get" "ComputerName" | trim }}

Run Scripts After macOS Updates

Automate tasks after system updates:

run_onchange_after_macos_update.sh.tmpl

{{- if eq .chezmoi.os "darwin" -}}
#!/bin/bash

# This will run whenever macOS is updated
# {{ output "sw_vers" "--buildVersion" }}

echo "macOS updated, running post-update tasks..."
# Your post-update commands here
{{ end -}}

Linux

Combine OS and Distribution Checks

Simplify nested conditionals:

dot_bashrc.tmpl

{{- if eq .osid "darwin" }}
# macOS-specific code
export BROWSER="open"
{{- else if eq .osid "linux-debian" }}
# Debian-specific code
export BROWSER="xdg-open"
{{- else if eq .osid "linux-fedora" }}
# Fedora-specific code
export BROWSER="xdg-open"
{{- end }}

Handle Package Managers

Different distributions use different package managers:

run_once_install_tools.sh.tmpl

#!/bin/bash

set -e

{{- if eq .osid "linux-ubuntu" }}
sudo apt update && sudo apt install -y build-essential
{{- else if eq .osid "linux-fedora" }}
sudo dnf groupinstall -y "Development Tools"
{{- else if eq .osid "linux-arch" }}
sudo pacman -S --noconfirm base-devel
{{- end }}

Windows

Detect Windows Subsystem for Linux (WSL)

Detect if running in WSL:

dot_bashrc.tmpl

{{- if eq .chezmoi.os "linux" }}
{{-   if (.chezmoi.kernel.osrelease | lower | contains "microsoft") }}
# WSL-specific configuration
export DISPLAY=$(cat /etc/resolv.conf | grep nameserver | awk '{print $2}'):0
export BROWSER="wslview"
{{-   end }}
{{- end }}

Run PowerShell Scripts as Admin

Self-elevate PowerShell scripts:

run_once_install_tools.ps1.tmpl

{{- if eq .chezmoi.os "windows" -}}
# Self-elevate the script if required
if (-Not ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole] 'Administrator')) {
  if ([int](Get-CimInstance -Class Win32_OperatingSystem | Select-Object -ExpandProperty BuildNumber) -ge 6000) {
    $CommandLine = "-NoExit -File `"" + $MyInvocation.MyCommand.Path + "`" " + $MyInvocation.UnboundArguments
    Start-Process -Wait -FilePath pwsh.exe -Verb Runas -ArgumentList $CommandLine
    Exit
  }
}

# Your elevated commands here
winget install Microsoft.VisualStudioCode
{{ end -}}

Create Symlinks on Windows

Enable symlink creation by turning on Developer Mode or setting the appropriate permission.

Containers and VMs

Detect Container Environments

dot_bashrc.tmpl

{{- if stat "/run/.containerenv" }}
# Running in Podman
export IN_CONTAINER=1
{{- else if stat "/.dockerenv" }}
# Running in Docker
export IN_CONTAINER=1
{{- end }}

Minimal Configurations for Containers

Use .chezmoiignore to skip unnecessary files in containers:

dot_chezmoiignore

{{- if or (stat "/run/.containerenv") (stat "/.dockerenv") }}
.config/autostart/
.local/share/applications/
{{- end }}

Hostname-Based Configuration

Simple Hostname Check

dot_gitconfig.tmpl

[user]
    name = Your Name
{{- if eq .chezmoi.hostname "work-laptop" }}
    email = you@work.com
{{- else if eq .chezmoi.hostname "personal-desktop" }}
    email = you@personal.com
{{- else }}
    email = you@default.com
{{- end }}

Hostname Patterns

Match multiple machines with similar names:

dot_bashrc.tmpl

{{- if hasPrefix "work-" .chezmoi.hostname }}
# Work machine settings
export WORK_ENV=1
export http_proxy="http://proxy.work.com:8080"
{{- end }}

Interactive Configuration

Prompt for machine-specific data during chezmoi init:

.chezmoi.toml.tmpl

{{- $email := promptString "email" -}}
{{- $work := promptBool "work machine" -}}

[data]
    email = {{ $email | quote }}
    work = {{ $work }}

Use the values in your dotfiles:

dot_gitconfig.tmpl

[user]
    name = Your Name
    email = {{ .email }}

{{- if .work }}
[http]
    proxy = http://proxy.work.com:8080
{{- end }}

Architecture-Specific Configuration

Handle different CPU architectures:

dot_bashrc.tmpl

{{- if eq .chezmoi.arch "amd64" }}
export ARCH="x86_64"
{{- else if eq .chezmoi.arch "arm64" }}
export ARCH="aarch64"
{{- end }}

Best Practices

Use Data Variables

Store complex logic in your config file template and expose simple variables:

.chezmoi.toml.tmpl

{{- $isWork := or (eq .chezmoi.hostname "work-laptop") (hasPrefix "work-" .chezmoi.hostname) -}}
{{- $isPersonal := not $isWork -}}

[data]
    isWork = {{ $isWork }}
    isPersonal = {{ $isPersonal }}

Use in templates:

dot_bashrc.tmpl

{{- if .isWork }}
export http_proxy="http://proxy.work.com:8080"
{{- end }}

Keep Templates Simple

Avoid complex logic in individual file templates. Put it in .chezmoi.toml.tmpl instead.

Test on All Machines

Before committing changes, test on all your machines:

# See what would change
chezmoi diff

# Apply changes
chezmoi apply

Document Your Variables

Add comments to your config template:

.chezmoi.toml.tmpl

# Detect chassis type (laptop vs desktop)
{{- $chassisType := "desktop" }}
# ... detection logic ...

# Prompt for email if not set
{{- $email := promptString "email" -}}

[data]
    # Used in .gitconfig and .bashrc
    email = {{ $email | quote }}
    # Used for power management settings
    chassisType = {{ $chassisType | quote }}

Troubleshooting

Debug Template Variables

Create a debug file to inspect available variables:

chezmoi execute-template '{{ . | toJson }}' | jq .

Test Templates

Test template rendering without applying:

chezmoi execute-template < ~/.local/share/chezmoi/dot_bashrc.tmpl

Check OS Release Info

On Linux, inspect /etc/os-release:

chezmoi execute-template '{{ .chezmoi.osRelease | toJson }}' | jq .

Documentation Index

​Detecting Machine Characteristics

​Determine Laptop vs. Desktop

​Detect CPU Cores and Threads

​Operating System Conditionals

​Basic OS Detection

​Linux Distribution Detection

​Platform-Specific Guides

​macOS

​Use Homebrew Bundle

​Get Stable Hostname

​Run Scripts After macOS Updates

​Linux

​Combine OS and Distribution Checks

​Handle Package Managers

​Windows

​Detect Windows Subsystem for Linux (WSL)

​Run PowerShell Scripts as Admin

​Create Symlinks on Windows

​Containers and VMs

​Detect Container Environments

​Minimal Configurations for Containers

​Hostname-Based Configuration

​Simple Hostname Check

​Hostname Patterns

​Interactive Configuration

​Architecture-Specific Configuration

​Best Practices

​Use Data Variables

​Keep Templates Simple

​Test on All Machines

​Document Your Variables

​Troubleshooting

​Debug Template Variables

​Test Templates

​Check OS Release Info

Detecting Machine Characteristics

Determine Laptop vs. Desktop

Detect CPU Cores and Threads

Operating System Conditionals

Basic OS Detection

Linux Distribution Detection

Platform-Specific Guides

macOS

Use Homebrew Bundle

Get Stable Hostname

Run Scripts After macOS Updates

Linux

Combine OS and Distribution Checks

Handle Package Managers

Windows

Detect Windows Subsystem for Linux (WSL)

Run PowerShell Scripts as Admin

Create Symlinks on Windows

Containers and VMs

Detect Container Environments

Minimal Configurations for Containers

Hostname-Based Configuration

Simple Hostname Check

Hostname Patterns

Interactive Configuration

Architecture-Specific Configuration

Best Practices

Use Data Variables

Keep Templates Simple

Test on All Machines

Document Your Variables

Troubleshooting

Debug Template Variables

Test Templates

Check OS Release Info