The Beauty of rsync and Backup Script

rsync is a command-line tool used to copy/clone files (“fast incremental file transfer“). It is a great, simple backup tool. The basic rsync command is this:

rsync -a src dest_dir

Where src is the original directory or file and dest_dir is the destination directory. Because rsync does incremental backups it only adds the file to the dest if it has been updated from the original backup.

rsync -axS src dest_dir

This is the command I use. This command can be used to backup just about anything! The options:

• -a means archive mode which basically means to preserve the file “as is” (same permissions…)
• -x means not to cross file systems boundaries
• -S means to handle sparse files efficiently
• -v option (verbose) can be used to print what rsync is doing

An important note about rsync: when src is a directory a trailing slash (/) tells rsync to copy the “contents” of the directory:

rsync -axS src_dir/ dest_dir
ls -1 dest_dir/
 file1
 file2

Without a trailing slash:

rsync -axS src_dir dest_dir
ls -1 dest_dir
 src_dir

rsync can also use file-lists containing paths of directories and files, to both include and exclude them for backup:

sudo rsync -axS --files-from="incl_file.txt" --exclude-from="excl_file.txt" src_dir dst_dir

src_dir will have to be specified and will have to be relative to paths in the file list:

cat incl_file.txt
Desktop/
rsync -axS --files-from="incl_file.txt" --exclude-from="excl_file.txt" /home/user/ dst_dir

rsync can also remove files from the dest_dir with the --delete option, so files that get added to the exclude file or taken out of the include file will removed from dest_dir.

rsync -axS --delete-excluded --files-from="incl_file.txt" --exclude-from="excl_file.txt" /home/user/ dst_dir

Backup Script

I use rsync to backup my system configurations and /home/ to make reinstalling easy. I created the script to remember the command to use, but to also easily add to the include and exclude files:

bcksysc i /etc/hostname 
 Added "/etc/hostname" to bcksysc-inc.txt include file.

Syntax:

bcksysc 
 bcksysc  - backup configurations
 i - add to the include list a file or folder
 e - add to the exclude list a file or folder
 c - create backup

Here’s the script all that needs to be done is to change the Parent Destination Directory (for backing up /home/ I copied the script to bckhome, changed the type to home and added /home/ to the include file):

So my destination directory looks like this:

ls -1 /run/media/todd/Backup/rsync/
 ...
 aspire_2012-08-31_sysc
 aspire_2012-08-31_home

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