# Archiver
Archiver is a bash script that helps you backup whatever you want, however you
want.

## Usage

For example:
`archive.json`
```json
[
  {
    "name": "Wallpapers",
    "target": "~/Media/Pictures/Wallpapers",
    "archive": {
      "name": "walls",
      "destination": "~/OneDrive/Wallpapers"
    },
    "timestamps": {
      "last_archive": 1712438594,
      "last_upload": 1712438693
    },
    "sync_command": "onedrive --synchronize --single-directory 'Wallpapers'",
    "md5sum": "6de26f11ad638fd145f3d1412e0bf1c6"
  },
  {
    "name": "Books",
    "target": "~/Documents/Books",
    "archive": {
      "name": "books",
      "destination": "~/OneDrive/Books"
    },
    "timestamps": {
      "last_archive": 1712439022,
      "last_upload": 1712439638
    },
    "sync_command": "onedrive --synchronize --single-directory 'Books'",
    "md5sum": "b4ae6185bb5a20d19c0b30f9778a10cb"
  }
]
```

You specify list of attribute sets with three key parts:
- `target`: the target directory you wish to backup
- `archive`: the name of the archive and where you want to store the archive
- `sync_command`: the command you wish to use to back up this specific directory

Other details like `timestamps` and `name` are useful for other purposes if you
wish to climb under the hood to use them.

The MD5-Sum is also useful if you wish to verify the legitimacy of your files
after retrieving them.

*PS:* an example `archives.json` is provided.

## Methodology
1. Your `target` gets converted into a tarball.
2. That tarball is compressed into an `xz` archive.
    - This format was chosen because of its excellent compression ratio.
    - Though in the future I would like to implement multiple formats for this.
3. A parity archive is created from that compressed tarball.
    - Uses the `par2cmdline` utilities.
    - A single block file with 30% redundancy is created.
    - Additionally, you can use the index file that's created but `par2` doesn't really need it.
4. A unix timestamp and MD5-Sum is taken from the archived tarball.
5. Your `sync_command` hook is run at the end and a secondary timestamp is taken
   at the end of this.
6. Your `archives.json` file is updated with all of the fresh timestamps and
   MD5-Sum.

## dependencies
- `tar`
- `xz`
- `stat`
- `par2create` (from `par2cmdline` package)
- `md5sum`
- `du`
- `awk`
- `jq`

## TODO
- [ ] Multiple archiving formats.
- [ ] Store `archives.json` in a user-specified directory.
- [ ] Multiple block file parity archive.
- [ ] Multi-threaded archiving.