---
name: "mrb"
section: "8"
platform: "linux"
package: "mrb"
version: "0.3+nmu2"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/mrb"
---

# mrb(8)

manage incremental snapshots with rsync/make.

## NAME

mrb - manage incremental snapshots with rsync/make.

## SYNOPSIS

**mrb** *command*

## DESCRIPTION

**mrb** is a simple aid to creating efficient incremental snapshots of a set, or sets, of directories whenever that may be required.  It may be used as part of a regular automated backup regime, or for manually checkpointing changes at convenient points in time.

## COMMANDS

The following commands are recognised (where '*MODULE*' is the name of one of your snapshot definitions):

- **new-***MODULE*

  Create a skeleton definition for a new snapshot '*MODULE*'.

- **dest-***MODULE*

  Create the destination dir for '*MODULE*'. This directory must exist to create a snapshot.

- **snap-***MODULE*

  Create a snapshot of '*MODULE*'.

- **sync**

  Create snapshots of all defined modules. If run as root this may be configured to include the modules of other users too (see MRB\_SYNC\_USERS in ~/.mrb/defaults).

- **help**

  Show mrb's own help text.

## CONFIGURATION FILES

### Per-user configuration

The following files may be used to specify global and local configuration options.

- */etc/default/mrb*

  system default configuration.

- *~/.mrb/defaults*

  per-user configuration.

### Per-user options

The following options control behaviour for all of a user's modules.

- **MRB\_SNAPSHOT\_LOG**

  An optional file path where transfer details will be recorded.  If unset these details will not be logged.

- **MRB\_SYNC\_USERS**

  A space separated list of users whose modules should be included in a **sync**. This is mostly only useful for root, as mrb will assume the identity of each user before creating snapshots of their modules.  If unset, only the invoking user's modules will be sync'ed.

- **MRB\_CONFDIR**

  An space separated list of the directories to search for module definition (\*.mrc) files.  They will be searched in the order given, with new modules added by default to the last one listed.  There should be few reasons to change the default value.

### Per-module configuration

The default **MRB\_CONFDIR** value will search for module definitions in:

- */etc/mrb/\*.mrc*

  - *~/.mrb/\*.mrc*

  Those created by **new-***MODULE* will be placed in this latter location by default.

### Per-module options

In each case *module* below is the name of the particular module that the value set should apply to.  These options should be defined in a file named *module*.**mrc**.

- **module\_SRC**

  A space separated list of the files and (top level) directories to include in the snapshots for this module.  These may be remote urls.

- **module\_DEST**

  The (local) directory root where snapshots of *module* should be stored.

- **module\_INCLUDE**

  An optional list of  [**rsync**(1)](/rsync/1.md) include patterns.

- **module\_EXCLUDE**

  An optional list of  [**rsync**(1)](/rsync/1.md) exclude patterns.

- **module\_FILTER**

  An optional list of  [**rsync**(1)](/rsync/1.md) filter patterns.

- **module\_FILTER\_FILE**

  An optional filename for  [**rsync**(1)](/rsync/1.md) dir-merge filtering support.

- **module\_RSYNC\_OPTIONS**

  Optional additional [**rsync**(1)](/rsync/1.md) options to pass verbatim when it is invoked.

- **module\_PRECOMMAND**

  An optional shell command to invoke just prior to creating a new snapshot. If the command does not return a successful exit status, then the snapshot creation will be aborted before it begins.  It may be used to mount removable media or similar.

- **module\_POSTCOMMAND**

  An optional shell command to execute after making the snapshot.  It will not be called if the snaphot creation failed at an earlier stage, and its return status may halt a sync operation if it fails with more modules still to process. It may be used, for example, to unmount removable media again.

- **module\_USER**

  An optional user name to check that mrb is running as before performing a snapshot.  This can be used to ensure you have the correct permisson to access the files being mirrored before you get too far.

## SEE ALSO

[**rsync**(1)](/rsync/1.md), [**make**(1)](/make/1.md).

## AUTHOR

mrb was written by Ron \<ron@debian.org\>.