I have two separate computers with the same MEDIA folder which is quite large. These folders have the same structure but in one computer there are more files.
What I would like to do is something like this:
1) Scan folder on computer A, create list of files I already have.
2) Copy list to a computer B and run "copy files that are not in the list" to my external drive.
Is it possible to do this with rsync?
Thank you so much, this would be really a powerful hack.
Sync a directory from one computer to another using an external drive, without copying the whole directory:
In the destination (computer A, in your case):
Generate the list of files you already have and save it to the external drive:
cd /PATH/TO/MEDIA
find -type f | cut -c2- > /PATH/TO/EXTERNAL/DRIVE/my_files
You have to cd to the folder you want to sync, so find will generate a list of files using relative paths.
In the origin (computer B, in your case):
Copy only the files you don't have to the external drive:
rsync -a --exclude-from=/PATH/TO/my_files /PATH/TO/MEDIA /PATH/TO/EXTERNAL/DRIVE
Make sure you don't include a trailing slash (/) in /PATH/TO/MEDIA.
Back to destination (computer A, in your case):
Copy the files from the external drive to your directory:
rsync -a /PATH/TO/EXTERNAL/DRIVE/MEDIA/ /PATH/TO/MEDIA
Now, make sure you do include a trailing slash in /PATH/TO/EXTERNAL/DRIVE/MEDIA/.
More info: Rsync manual page.
