bash command to copy file from one computer to another
You can use scp (Secure Copy).
To copy FROM your machine to friends:
scp file_to_copy user@remote.server.fi:/path/to/location
In another direction:
scp user@remote.server.fi:/path/locatio/file_name file_name
If you need to copy an entire directory, you'll need to use the recursive flag, like this:
scp -r directory_to_copy user@remote.server.fi:/path/to/location