Backing up and verifying files in Mac OS

March 3rd, 2009  |  Published in Recipes, technology

There are some interesting backup tools for system backups (Time Machine) but I want to just be able to copy and verify a directory (and its children).  I’ve heard that the commercial product Retrospect provides copy and verify functionality, but I’m cheap.

This is the method that I used.  I’d be interested on hearing feedback about it:

# Copy the files using ditto 
$ ditto /Volumes/Backup/columbus_da/ /Volumes/ghingexternal/columbus_da

# Get md5s for the original and copied files
$ find /Volumes/ghingexternal/columbus_day/ -exec md5 '{}' \; > md5s-new.txt
$ find /Volumes/Backup/columbus_day/ -exec md5 '{}' \; > md5s-old.txt

# Strip out the directory prefix from the md5 files
$ mv md5s-old.txt md5s-old.txt.bak
$ mv md5s-new.txt md5s-new.txt.bak
$ sed 's/\/Volumes\/ghingexternal\///' md5s-new.txt.bak > md5s-new.txt
$ sed 's/\/Volumes\/Backup\///' md5s-old.txt.bak > md5s-old.txt

# Compare the md5s of the copied files
$ diff md5s-old.txt md5s-new.txt