# Backup
A flexible backup script for backing up linux system using rsync, ssh, cron and other common shell commands.

## Usage

First add your settings at the top of the file and then add a cronjob to periodically execute the script. In the following paragraphs the settings will be explained.

`SOURCES` is an array containing the paths to the folders that should be included in the backup.

`TARGET` the absolute path to the folder where the backup will be saved to. If the `TOSSH` option is used, this should of course be the absolute path on the remote system.

`EXCLUDEFROM` a path to a file containing folders and files that should be excluded from a backup.

`MAILADRESS` if this option is a non empty string, the log of the backup will be send to the email adress contained in this string. For this to work the `mail` command must be set up properly.

`LISTPACKAGES` if this option is set to a non empty string the log of the backup will contain a list of installed packages. For this command to work the `dpkg` command must be installed properly. 

`LOG` the name of the log file.

`RSYNCCONF` an array that contains additional rsync flags.

`TOSSH` if this option is set to a non empty string, the backup will be saved on the remote host that this string refrences. **Attention:** Please set the `TOSSHUSER` and `TOSSHPORT` options as well, otherwise the script will probably fail to create a backup successfully. 

`FROMSSH` if this option is set to a non empty string the folders refrenced in `SOURCES` will be fetched from the remote host refrenced by this string. **Attention:** Please set the `FROMSSHUSER` and `FROMSSHPORT` options as well otherwise the script might fail to create a backup successfully. 

**Attention:** If both the `TOSSH` & `FROMSSH` options are set the script will fail!

`WEEKS` the number of weeks for which we will safe backups for. 

### Settings example

```bash
## General Settings
SOURCES=(/home/example)           # What folder should be saved?
TARGET="/home/backup/example"     # Where should they be saved? (absolute path!)
EXCLUDEFROM="~/exclude.txt"       # What files are supposed to be excluded?
MAILADRESS="example@example.com"  # To which email adress should the logs be sent?
LISTPACKAGES=""                   # Change to non empty string to save a list of 
                                  # installed packages!
LOG=$0.log                        # Log file name & location
RSYNCCONF=(--delete)              # Additional rsync flags  

## SSH Settings
TOSSH="my.backup.com"             # What ssh server stores the backups?
FROMSSH=""                        # From what ssh server should the files be 
                                  # backuped?
                                  # For several reasons TOSSH and FROMSSH cannot
                                  # be used at the same time!
TOSSHUSER="backup"                # The ssh user of the system on which the 
                                  # backup will be created
TOSSHPORT=22                      # The ssh port of the system on which the 
                                  # backup will be created  
FROMSSHUSER=""                    # The ssh user of the system from which the 
                                  # files will be backed up
FROMSSHPORT=22                    # The ssh port of the system from which the 
                                  # files will be backed up
WEEKS=5                           # For how many weeks shall we save backups? 
                                  # This will keep weekly backups for at most 5 
                                  # weeks.
```

### Crontab example
Create a backup every two hours (use flock to prevent duplicate scripts from running):

```bash
0 */2 * * * flock -n ~/backup.lock ~/backup.sh
```

### Exclude file example
This example can be used for a full system backup (use only "/" as source for a full system backup). Copied from the [Arch Wiki](https://wiki.archlinux.org/index.php/rsync#Full_system_backup).

```
/dev/*
/proc/*
/sys/*
/tmp/*
/run/*
/mnt/*
/media/*
/lost+found
```

## Inspiration

- [Backup mit RSYNC](https://wiki.ubuntuusers.de/Skripte/Backup_mit_RSYNC/)
- [rsync linux backup script](https://ctaas.de/rsync.htm)
- [Easy Automated Snapshot-Style Backups with Linux and Rsync](http://www.mikerubel.org/computers/rsync_snapshots/)