SCP: securely copying files to/from another Linux machine

scp oldfile username@hostname.iu.hio.no:newfile
Copy the local file oldfile to the file newfile on the remote host hostname.iu.hio.no as the user username

scp username@hostname.iu.hio.no:oldfile newfile
Copy the file oldfile on the remote host hostname.iu.hio.no as the user username to the local file newfile