Copying-files-over-SSH.md

The general workflow for coding assignments in 240 is:

1. Do the assignment
2. Hand in your files with handin240
3. Upload the generated PDF to Gradescope

That last step may be complicated if you're not working at a lab computer. The PDF is located on an ECE machine, but you need to upload from your local machine...the way we do that is using scp or sshfs.

What is scp?

scp, or secure copy is a tool that allows us to copy files remotely. It is functionally identical to cp (for the most part), with the added remote functionality.

In 240, there will be times where you want to copy files from your local machine to the ECE servers, and vice versa which is why you'll need to scp.

How to use scp

Just like cp, the structure of an scp command is

scp path/to/sourcefile path/to/destfile

The thing to note is whenever you want to specify a remote directory, you have to add its address.

For example, say you want to copy a file foo.txt from your local machine (located at the folder ~/docs/foo.txt) to your private directory on the Unix machine (located at unix.andrew.cmu.edu):

scp ~/docs/foo.txt <andrewid>@unix.andrew.cmu.edu:~/private

A couple things to note:

1. You need to provide your login (your Andrew ID), then @ followed by the hostname (unix.andrew.cmu.edu).
2. After the hostname, you must put a colon (:) followed by the path to the directory you want on remote. Note that there is no space after the colon.

In other words a remote path has the form

username@hostname:path/to/file

Using SSH shortcuts with SCP

If you followed the guidance for setting up SSH shortcuts then you can substitute everything before the : with your shortcut.

So the remote path now becomes

ece:path/to/file

which is pretty neat.

sshfs

On GNU/Linux and other Unix-like systems (and maybe OS X?), you can mount a remote filesystem you can ssh into with sshfs. See this guide for instructions.