Filename Rules

If you name your files carefully, Grimoire can use that. Filename rules teach it what your naming scheme means:

• Folder naming patterns describe how the books in a folder are named. Grimoire reads each new book's title (and publisher, version, year, ...) out of its filename, and can rename existing files to match - or move them from an old scheme onto a new one.
• Variant filename rules are your library's own markers for variants - GL_ for a gridless map, -pf for a printer-friendly PDF - so duplicate detection pre-fills them the way it already does for nogrid or printer friendly.

Both live under Settings → Library → Files & folders and are admin only. Files are never renamed unless you ask.

Folder naming patterns

Take a file named:

D&D5e - [Loot Tavern] - adventure L2,7,12 - Crystallica (v0.99, 2026).pdf

With this pattern on its folder:

{system} - [{publisher}] - {*} - {title}< (v{version}, {year})>

the book shows as Crystallica, published by Loot Tavern, version 0.99, from 2026. The filename itself is unchanged.

Pattern syntax

Plain text has to appear in the filename as written (case and the width of spaces don't matter). Each {field} matches the part of the name in its place.

Field	When reading a filename	When renaming
{title}	The book's title - required in every pattern	✓
{publisher}, {version}, {isbn}, {product_code}	Fill those fields	✓
{authors}	Authors, split on ,, & and and	✓
{year}	A four-digit year	✓
{system}, {category}, {language}, {date}	Must match, but aren't kept	✓
{*}	Anything, thrown away	✗

• {*} lets a pattern pick out the title without describing the rest of the name. A pattern with {*} can read titles but can't rename files.
• < ... > marks an optional part: {title}< (v{version})> matches Crystallica.pdf and Crystallica (v2).pdf. When renaming, an optional part is dropped if a field inside it is empty.

A pattern holds at most 20 fields, {*} included.

Titles from filenames

New books under a folder with a pattern take their title from the filename when it fits the pattern, along with any publisher, authors, year, version, ISBN and product code the pattern names. A sidecar .opf still wins.

For books already in the library, open the pattern, check the preview and choose Update titles. Titles are overwritten; the other fields are only filled where a book has none, so anything you typed in by hand stays.

This works on a read-only library - it never touches the files.

Renaming files to match

A pattern without {*} also works in reverse: Grimoire writes each book's filename from its metadata. The preview shows every new name and flags the ones it won't rename - a required field is empty, the name is over 255 bytes, or another file already has it - and warns when a full path would pass Windows' 260-character limit.

Tick the books you want and choose Rename files. Each book keeps its tags, favourites, reading progress, campaign links and sidecars, exactly as with a rename in the file manager. Renaming needs a writable library, and only ever happens when you ask for it.

Which pattern applies

A pattern covers its folder and every folder beneath it; when two apply, the one nearest the book wins. Renaming or moving a folder in the file manager takes its pattern along, and deleting the folder deletes it.

Variant filename rules

When duplicate detection pairs two copies of something, it guesses what kind of variant each is from the filenames. Add rules for your own markers:

Match	Text	Kind	Label
Starts with	GL_	Gridless
Whole word	night		Night
Ends with	-pf	Printer friendly

• Whole word matches complete words of the name, so grid doesn't match Gridiron Tavern. Starts with / Ends with test the name without its extension. Case is ignored.
• A rule can set a kind, a label, or both, and can be limited to one collection.
• A rule only counts when one copy matches and the other doesn't.
• Rules run top to bottom, before the built-in markers, so your convention wins.

Suggestions are only ever a starting point - linking variants is always your call. New rules apply to the next duplicate scan and to any comparison you open.