Apply

grim apply renders the grimoire’s files/ tree and places it under a target root (default $HOME). It is grim’s replacement for chezmoi apply — scoped deliberately to one user’s needs, which is what keeps it small (ADR 0002).

The source tree

A grimoire’s files/ directory mirrors the target tree. Attributes are encoded in path-component names and applied per component, so they work for both files and directories:

source component	target	effect
dot_zshrc	.zshrc	leading-dot rename
dot_config/	.config/	same, for directories
executable_setup	setup (mode 755)	mark executable
private_dot_ssh/	.ssh/ (mode 700)	restrict permissions (file: 600)
gitconfig.tmpl	gitconfig	render as a template (suffix stripped)

Attributes combine in the order [executable_|private_] dot_ name [.tmpl] — e.g. executable_dot_script.tmpl → .script, mode 755, templated. Source entries beginning with a literal . (like .git) are ignored.

The template context

Templates are MiniJinja (Jinja2-compatible). A template sees:

• facts — the detected machine, e.g. {{ facts.os }}, {{ facts.arch }}, {{ facts.hostname }}, {{ facts.cpu_features }}.
• platforms — the active platform names, highest precedence first, e.g. {% if "workstation" in platforms %}…{% endif %}.
• isolation_id — the per-platform install-tree namespace, e.g. {{ isolation_id }}.

# ~/.demo-grimrc, rendered for {{ facts.hostname }} ({{ facts.os }}/{{ facts.arch }})
{% if "workstation" in platforms -%}
EDITOR=nvim
{%- else -%}
EDITOR=vim
{%- endif %}

Trailing newlines are preserved (config files should end with one).

Apply = render → diff → atomic write

For each source entry, grim computes the target path, mode, and content (rendering templates), then compares against what’s on disk:

• create — the target doesn’t exist.
• update — it exists but differs (a unified diff is computed for text files).
• unchanged — it already matches; skipped.

Writes go to a temp file in the target directory and are renamed into place, so a reader never sees a partial file. --dry-run stops after the diff and writes nothing.

Commands

grim apply --grimoire <dir> [--target <root>] [--dry-run]
grim diff  --grimoire <dir> [--target <root>]   # a dry-run apply that shows the diffs

--grimoire is the grimoire directory (containing grimoire.toml and files/); --target defaults to $HOME. Try it against the bundled example:

grim diff  --grimoire examples/demo --target /tmp/grim-demo
grim apply --grimoire examples/demo --target /tmp/grim-demo

Status & what’s next

Implemented: the naming convention, the MiniJinja render context, plan/diff/atomic-apply, modes on Unix. Not yet: symlink sources, deletion of files grim previously managed (state tracking), and sourcing the chezmoi home/ tree via an importer. See the roadmap.