Having one or more backups is essential.
Sooner or later, you most likely will have something go
wrong and lose your personal files, documents or photos.
Examples include accidentally deleting the wrong files,
hardware failure, losing your laptop or infecting your
computer. At times like these, backups are often the only
way you can rebuild your digital life.
OUCH! -- Backup & Recovery
Use Time Machine to back up or restore your Mac
Backup to external HD or SSD, via command line
if -e /Volumes/SSD1 rsync -av `pwd`/ `pwd | sed s."/Users/swormley"."/Volumes/SSD1".`
if -e /Volumes/SSD2 rsync -av `pwd`/ `pwd | sed s."/Users/swormley"."/Volumes/SSD2".`
if -e /Volumes/SSD3 rsync -av `pwd`/ `pwd | sed s."/Users/swormley"."/Volumes/SSD3".`
if -e /Volumes/SSD4 rsync -av `pwd`/ `pwd | sed s."/Users/swormley"."/Volumes/SSD4".`
Recall Dropbox (Free service for all platforms)
Dropbox is a file hosting service operated by Dropbox, Inc.,
headquartered in San Francisco, California, that offers
cloud storage, file synchronization, and client software.
Dropbox allows users to create a special folder on each of
their computers, which Dropbox then synchronizes so that it
appears to be the same folder (with the same contents)
regardless of which computer is used to view it. Files
placed in this folder also are accessible through a website
and mobile phone applications.
Using The Cloud Securely
iCloud Backup & Storage
Best way to backup a Mac
Backblaze (backup in the cloud)
Carbonite (backup in the cloud)