rsync

Using rsync for backup and restore

The rsync utility will synchronize files between two separate directories or file systems. It is like a copy, but does not copy all of the files all of the time. Instead, it copies only those files that have changed.

I use little shell scripts so that I don’t have to remember all of the settings every time I use them.

I keep all of these files in the bin sub-directory of my home directory. I keep that as one of the directories on my PATH environment variable.

Backup

backup.sh is the script for making a backup.

The directory /Users/dclo/bkp_test_dir is the test directory that I want backed-up. The directory /Volumes/lAvionBackup is the mounted location of the backup disk.

The script uses a file, bkp.skip.list with a list of directories to skip (not copy).

Among those directories is the place that iTunes puts movies.
Another is the place where browsers keep their caches.
Another is the place where Docker keeps its images.
The ubiquitous MacOS .DS_Store files

The main reason to skip those is that they contain large amounts of data that is readily recoverable from elsewhere. This helps reduce the size of the backups and the time needed to make them.

A second thing the script does is clean-up the log files that Mac OS keeps on my computer. These build-up over time and take-up space.

Restore

restore.sh is the script for restoring a backup.

The rsync command going the other way is similar, however, I don’t want it to delete or exclude any files. It preserves file permissions and times.

rsync is a little tricky about directories. In the source specification, ending with a slash means to put the contents of the directory in the destination. Without the ending slash, it creates the named directory in the destination.