I'm on macOS and, for context, I have one main hard drive that should include all my files (and yes, it's backed up with redundancy). And I have many other smaller hard drives that I have used over the years and have copied the contents to the main drive.
Now I want to discard the smaller HDDs, but want to make sure I don't lose anything.
The folder structure on the main drive might differ from the original folder structure in the smaller drives.
How can I compare two hard drives (or folders for that matter) and find files that are missing in one of them, disregarding their folder structure?
12 Answers
Beyond Compare (Scooter Software) is very good software for this task (Drive and Folder compares) and is reasonably economical.
There are versions for Mac, Windows and Linux.
I use Beyond Compare to compare hard drives when I have copied A to B and made changes to one drive after the copy.
2COMPARE FILES, FOLDERS
You can compare entire drives and folders at high speed, checking just sizes and modified times. Or, thoroughly verify every file with byte-by-byte comparisons. FTP sites, cloud storage, and zip files are integrated seamlessly, and powerful filters allow you to limit what you see to only what you're interested in.
Once you've found specific files you're interested in, Beyond Compare can intelligently pick the best way to compare and display them. Text files can be viewed and edited with syntax highlighting and comparison rules tweaked specifically for documents, source code, and HTML. The text contents of Microsoft Word .doc and Adobe .pdf files can also be compared but not edited. Data files, executables, binary data, and images all have dedicated viewers as well, so you always have a clear view of the changes.
Compare files
Side-by-side display
Color highlighting of differences within lines
Display filters to show only differences
Jump to next/previous difference within file or folder
Printed and HTML comparison reports
Unicode and MBCS support
Thumbnail overview of comparison
Can convert files before comparing them
Compare files or clipboard contents
Automatic backups when saving
I use FreeFileSync , it has many options including updating a slave from a master or mirroring both sides, checking based on hash or timestamp, etc. I don't think it will compare files regardless of directory structure but that doesn't seem to make sense to me as there are many identically named files that can have different content/purpose depending on where it is in the directory structure.
If you want to minimize disk usage in archives might be worth using something like dupeGuru to remove identical files. Maybe you could consolidate everything into a drive then use this to weed out duplicates in different locations.
