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Final modifications to this document (#2580)
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@jimcat8
jimcat8 authored Jan 15, 2025
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73 changes: 42 additions & 31 deletions docs/books/admin_guide/09-backups.md
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Expand Up @@ -554,26 +554,40 @@ It is possible to extract all or part of a backup.
Unlike the `tar` command, there is no option to backup and compress simultaneously.
So, it is done in two steps: backup and compression.

To perform a backup with `cpio`, you must specify a list of files to backup.
`cpio` has three operating modes, each corresponding to a different function:

This list is provided with the commands `find`, `ls` or `cat`.
1. **copy-out mode** - Create a backup (archive). You can enable this mode through the `-o` or `--create` options. In this mode, you must generate a list of files with a specific command (`find`, `ls` or `cat`) and pass it to cpio.

* `find` : browses a tree, recursive or not;
* `ls` : lists a directory, recursive or not;
* `cat` : reads a file containing the trees or files to be saved.
* `find` : browses a tree, recursive or not;
* `ls` : lists a directory, recursive or not;
* `cat` : reads a file containing the trees or files to be saved.

!!! Note
!!! Note

`ls` cannot be used with `-l` (details) or `-R` (recursive).

It requires a simple list of names.

2. **copy-in mode** – extracts files from an archive. You can enable this mode through the `-i` option.
3. **copy-pass mode** – copies files from one directory to another. You can enable this mode through the `-p` or `--pass-through` options.

Like the `tar` command, users need to pay attention to how the file list is saved (**absolute path** or **relative path**) when creating an archive.

`ls` cannot be used with `-l` (details) or `-R` (recursive).
secondary function:

It requires a simple list of names.
1. `-t` - Print a table of contents of the input.
2. `-A` - Append to an existing archive. Only works in copy-in mode.

### Create a backup with `cpio` command
!!! note

Some options of `cpio` need to be combined with the correct operating mode to work properly, see `man 1 cpio`

### copy-out mode

Syntax of the `cpio` command:

```bash
[files command |] cpio {-o| --create} [-options] [<file-list] [>device]
[files command |] cpio {-o| --create} [-options] [< file-list] [> device]
```

Example:
Expand All @@ -590,17 +604,17 @@ Using the name of a backup media:
find /etc | cpio -ovF /backups/etc.cpio
```

The result of the `find` command is sent as input to the `cpio` command via a *pipe* (character `|`, ++alt-graph+6++).
The result of the `find` command is sent as input to the `cpio` command via a *pipe* (character `|`, ++left-shift+backslash++).

Here, the `find /etc` command returns a list of files corresponding to the contents of the `/etc` directory (recursively) to the `cpio` command, which performs the backup.

Do not forget the `>` sign when saving or the `F save_name_cpio`.

| Options |Description |
|---------|------------------------------------------------|
| `-o` |Creates a backup (*output*). |
| `-o` |Create a backup through _cp-out_ mode. |
| `-v` |Displays the name of the processed files. |
| `-F` |Designates the backup to be modified (medium). |
| `-F` |Backup to specific media, which can replace standard input ("<") and standard output (">") in the `cpio` command |

Backup to a media:

Expand All @@ -613,17 +627,13 @@ The media can be of several types:
* tape drive: `/dev/rmt0`;
* a partition: `/dev/sda5`, `/dev/hda5`, etc.

### Type of backup

#### Backup with relative path
#### Relative and absolute paths of file list

```bash
cd /
find etc | cpio -o > /backups/etc.cpio
```

#### Backup with absolute path

```bash
find /etc | cpio -o > /backups/etc.A.cpio
```
Expand All @@ -634,10 +644,10 @@ find /etc | cpio -o > /backups/etc.A.cpio

If the path indicated in the `find` command is **relative**, then the backup will be done in **relative**.

### Add to a backup
#### Append files to existing backups

```bash
[files command |] cpio {-o| --create} -A [-options] [<fic-list] {F|>device}
[files command |] cpio {-o| --create} -A [-options] [< fic-list] {F| > device}
```

Example:
Expand All @@ -650,10 +660,10 @@ Adding files is only possible on direct access media.

| Option | Description |
|--------|---------------------------------------------|
| `-A` | Adds one or more files to a backup on disk. |
| `-A` | Append one or more files to an existing backup. |
| `-F` | Designates the backup to be modified. |

### Compressing a backup
#### Compressing a backup

* Save **then** compress

Expand Down Expand Up @@ -682,13 +692,13 @@ For the first method, the backup file is automatically renamed by the `gzip` uti
Syntax of the `cpio` command to read the contents of a *cpio* backup:

```bash
cpio -t [-options] [<fic-list]
cpio -t [-options] [< fic-list]
```

Example:

```bash
cpio -tv </backups/etc.152.cpio | less
cpio -tv < /backups/etc.152.cpio | less
```

| Options |Description |
Expand All @@ -700,18 +710,18 @@ After making a backup, you need to read its contents to ensure there are no erro

In the same way, before performing a restore, you must read the contents of the backup that will be used.

### Restore a backup
### copy-in mode

Syntax of the `cpio` command to restore a backup:

```bash
cpio {-i| --extract} [-E file] [-options] [<device]
cpio {-i| --extract} [-E file] [-options] [< device]
```

Example:

```bash
cpio -iv </backups/etc.152.cpio | less
cpio -iv < /backups/etc.152.cpio | less
```

| Options | Description |
Expand Down Expand Up @@ -759,7 +769,7 @@ cpio --no-absolute-filenames -divuF home.A.cpio
* Restore a relative backup

```bash
cpio –iv <etc.cpio
cpio –iv < etc.cpio
```

* Absolute restoration of a file or directory
Expand Down Expand Up @@ -805,9 +815,9 @@ The file receives the extension `.gz`.

It keeps the same rights and the same last access and modification dates.

### Compressing with `bunzip2`
### Compressing with `bzip2`

The `bunzip2` command also compresses data.
The `bzip2` command also compresses data.

Syntax of the `bzip2` command:

Expand Down Expand Up @@ -851,7 +861,8 @@ The file name is truncated by `gunzip` and the extension `.gz` is removed.

* `.z` ;
* `-z` ;
* `_z` .
* `_z` ;
* `-gz` ;

### Decompressing with `bunzip2`

Expand Down

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