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Configuration file

Deucalion keeps its settings in ~/.config/deucalion/config.json (or $XDG_CONFIG_HOME/deucalion/, or $DEUCALION_CONFIG_DIR). The app and the commands change it for you; you rarely need to edit it. deucalion config show prints it with the default values filled in; deucalion config edit opens it in your editor. It is a JSON file: keep the quotes, commas and brackets.

Missing keys take their default value. Your backup drives' passwords are never stored here.

Keys

version

The file's format version. Default: 1. Don't change it.

targets

Your registered backup drives, by id:

"targets": {
  "fcf91aec-…": {
    "name": "Alex Backup",
    "path": "/media/alex/Alex Backup/Deucalion-Backup",
    "registered": "2026-10-11T23:16:38+01:00",
    "allow_internal": false,
    "access": { "method": "veracrypt", "kind": "partition", "partuuid": "…",
                "mount_name": "Alex Backup", "plain_uuid": "…" }
  }
}
Key Meaning
name The drive's name.
path Where its backup folder was last found (updated automatically when it is mounted elsewhere).
registered When it was first registered.
allow_internal For testing only.
access How to unlock it: see drive.json. {"method": "none"} for unencrypted drives.

Default: {}. Use the app's Drives page, setup-drive, register and open to change it. To stop using a drive from the command line, remove its entry here (or use Forget in the app).

default_target

The id of the drive backups go to. Default: null (the only drive, if there is one). Change it with the star button on the Drives page or deucalion register <backup folder> --default.

home_path

The home folder to back up. Default: null (your own home folder). Set only for special cases, for example testing.

home_excludes

What is left out of your home folder: a list of patterns. Default: the default exclusions. Changed by Settings and deucalion exclude.

extra_folders

Folders outside your home folder that full backups include:

"extra_folders": [
  { "name": "shared", "path": "/srv/shared", "excludes": [] }
]
Key Meaning
name Short name; the folder is stored in the backup under extras/<name>.
path The folder.
excludes Patterns left out of this folder, relative to it. Only editable here.

Default: []. Changed by Settings → Extra folders and deucalion folder.

profiles

Named lists of paths for partial backups: {"work": ["/home/alex/Projects", "/home/alex/Documents/Work"]}. Default: {}. Changed by deucalion profile.

keep_overwritten

true: the previous version of a changed file goes to Removed Files. false: it is replaced directly (files deleted from your computer still go to Removed Files). Default: true. Changed by Settings → Keep old versions of changed files.

system_recipe

true: full backups save the system recipe. Default: true. Changed by Save system settings (Back Up page and Settings). On the command line, --no-system skips it once.

system_admin

true: full backups also save the protected settings (asks for the administrator password). Default: true. Changed by Include protected settings. On the command line, --no-admin skips it once.

A complete example

The demo configuration:

$ deucalion config show
{
  "version": 1,
  "targets": {
    "f7721c0e-a587-44de-a199-2d74f9c20b4e": {
      "name": "Alex Backup",
      "path": "/media/alex/Alex Backup2/Deucalion-Backup",
      "registered": "2026-10-12T09:08:19+01:00",
      "allow_internal": false,
      "access": {
        "method": "veracrypt",
        "kind": "partition",
        "partuuid": "357b958c-3642-4038-828f-af744ee22801",
        "mount_name": "Alex Backup",
        "plain_uuid": "EFFC-B52F"
      }
    }
  },
  "default_target": "f7721c0e-a587-44de-a199-2d74f9c20b4e",
  "home_path": null,
  "home_excludes": [
    ".cache/",
    ".thumbnails/",
    ".local/share/Trash/",
    ".local/share/recently-used.xbel",
    ".local/share/containers/",
    ".var/app/*/cache/",
    ".npm/_cacache/",
    ".config/**/Cache/",
    ".config/**/Code Cache/",
    ".config/**/GPUCache/",
    ".config/**/DawnCache/",
    ".config/**/DawnGraphiteCache/",
    ".config/**/DawnWebGPUCache/",
    ".config/**/GrShaderCache/",
    ".config/**/ShaderCache/",
    ".config/**/CacheStorage/",
    ".config/**/CachedData/",
    ".config/**/CachedExtensionVSIXs/",
    "Videos/",
    "node_modules/"
  ],
  "extra_folders": [
    {
      "name": "shared",
      "path": "/srv/shared",
      "excludes": []
    }
  ],
  "profiles": {
    "work": [
      "/home/alex/Projects",
      "/home/alex/Documents/Work"
    ]
  },
  "keep_overwritten": true,
  "system_recipe": true,
  "system_admin": true
}