When the user assumes `-p` does the same for scp as it does for ssh, funny things happen:

  touch myfile
  scp -p 22 myfile targetmachine:targetfile

The above prints "scp: targetfile: No such file or directory", which, while true (there is no file called "targetfile" on the host -- the users intent was to put it there), is a very confusing error message.

The problem here is that `-p` doesn't accept an argument for scp as it does for ssh, and so "22" is treated as a file name. It is the file "22" that doesn't exist.

Let's

  touch ~/targetfile

on `targetmachine`. What happens then?

  $ scp -p 22 myfile zh.nh2.me:targetfile
  scp: targetfile: Not a directory

Certainly true, targetfile is not a directory. Nevertheless, not quite the error message the user would hope for.

What if we make `targetfile` a directory then (`rm ~/targetfile && mkdir targetdir` on targethost)?

  $ scp -p 22 myfile zh.nh2.me:targetdir
  22: No such file or directory
  myfile                     100%    0     0.0KB/s   00:00

Finally an error message that points out what the user did wrong.

Would it be possible to improve scp's error messages, such that for this very common error of using `-p` incorrectly, the earlier examples point out more helpfully to the user that "22" doesn't exist?

Thanks!