scp

scp source target 
scp root@source_server:/app/file1.txt  /backup
scp file1.txt  root@target_server:/app
scp root@source_server:/app/file1.txt  root@target_server:/app

$ scp myfile.txt remoteuser@remoteserver:/remote/folder/
$ scp remoteuser@remoteserver:/remote/folder/remotefile.txt  localfile.txt