Incremental Backup using TAR
Snippet code for backing up data using tar.
Snippet code for incremental backup can be found here.
Incremental Backup using TAR
The following shell script perform incremental backup using TAR.
It mounts a pendrive and then backs up all subdirectories under /home/daniel, as a compressed .tar.gz file, to the target pendrive (excluding some directories which do not require backup, such as cache, dropbox, etc). Finally, the pedrive is unmounted.
The backup-snapshot.file is the file used to control the increments, and it is managed by TAR itself.
Snippet
#!/bin/bash
SRC_PATHS='/home/daniel'
DIRS_TO_EXCLUDE='--exclude=Dropbox --exclude=tmp --exclude=.cache --exclude=.mozilla --exclude=.IdeaIC2018.2 --exclude=.m2 --exclude=.npm --exclude=.Trash-1000 --exclude=.v8* --exclude=.vagrant.d'
DEST_PATH=/home/daniel/tmp/pendrive
mount /dev/sdb1 $DEST_PATH
if grep -qs $DEST_PATH /proc/mounts; then
tar --listed-incremental=/home/daniel/data/backup-snapshot.file $DIRS_TO_EXCLUDE -cvpzf $DEST_PATH/backup-`date +%y-%m-%d-%H-%M-%S`.tar.gz $SRC_PATHS
umount $DEST_PATH
fi
The script above can be added to crontab to perform daily incremental backups, with the following entry (to backup everyday at 21pm, for instance): 00 21 * * * /home/daniel/code/script/backup.sh.
Final notes
To extract (and preserve the final state) of overall backup, for each backup file in order, use the param --listed-incremental=/dev/null. e.g.:
tar --listed-incremental=/dev/null -xvf backup-19-02-24.tar.gz tar --listed-incremental=/dev/null -xvf backup-19-02-25.tar.gz
and so forth.
