scp, rsync and sftp.
WHAT scp DOES
Copies over an SSH connection.
WHAT ITS WEAKNESS IS
It restarts from the beginning if interrupted.
WHAT rsync DOES
Copies only differences, and resumes.
WHY IT IS THE BETTER TOOL
On a slow or unreliable connection, it is the difference between finishing and not.
WHAT THE USEFUL OPTIONS ARE
Archive mode, preserving permissions and timestamps Compression Progress display Partial, keeping incomplete transfers for resumption Delete, removing what is absent at the source
WHY THE DELETE OPTION DESERVES CARE
It removes files at the destination, and a wrong path removes the wrong things.
WHAT TO DO BEFORE USING IT
Run with the dry-run option and read the output.
WHAT THE TRAILING SLASH MEANS
With it, the contents of the directory are copied; without it, the directory itself.
WHY THAT MATTERS
It is the commonest rsync mistake, producing a nested duplicate.
WHAT sftp PROVIDES
An interactive file transfer session over SSH.
WHAT TO USE FOR VERY LARGE TRANSFERS HERE
rsync, in a persistent session, with compression.
WHY
Connections drop, and restarting a large transfer is expensive in time and data.
WHAT TO VERIFY AFTER ANY TRANSFER
Counts and sizes, and that a sample file opens.
