SSH and Remote Access
You’ll be using SSH to log in to lily/iris to do your work in this class. SSH (Secure SHell) is a way to open a shell/terminal on a remote computer. This allows you to interact with the remote computer and run programs, edit files, write code, etc. SSH is a secure shell because it uses an encrypted channel for communication between your local computer and the remote computer.
The program ssh is used to connect to a remote machine. Use ssh username@host to connect to the computer named host (e.g., lily.rhodes.edu) with the given username (e.g., langm). For example, my account on lily is named langm. To connect, I run ssh langm@lily.rhodes.edu.
Access from off-campus
Within the first week, you should have access to the Rhodes VPN. Follow the instructions on the software resources page to install the FortiClient software.
Passwordless SSH
You can set up SSH so that you don’t need to enter your password each time. To do so, you’ll need to generate a public/private key pair, and copy the public key to the remote computer.
Do the following on your local computer:
$ ssh-keygen -t rsa -b 4096 -C "your_email@address.com"
Hit enter to accept the default file location. When it prompts you for a password, just hit enter–do not enter a password!
Now, copy you newly-generated SSH id to the remote machine:
$ ssh-copy-id user@lily.rhodes.edu
Now you should be able to log in without using a password.
Passwordless ssh between lily/iris
To SSH between lily and iris without using a password, follow the same step running ssh-keygen while you are logged in to lily. Then, simply do the following:
$ cat .ssh/id_rsa.pub > ~/.ssh/authorized_keys
Now you should be able to simply run ssh iris to connect to iris without a password.
Transferring files with SCP
If you want to transfer files back and forth between a remote computer, you can use the program SCP (Secure CoPy). This is a SSH version of the cp command.
Recall that using cp copies a source file/directory to a dest file/directory:
$ cp source dest
scp is similar, except it allows you to specify a different host machine before the source or dest:
# copy remote to local
$ scp user@host:/path/to/souce dest
# copy local to remote
$ scp source user@host:/path/to/dest
Practically, if I want to copy a file from my laptop to my home directory on iris, this would look like the following:
$ scp my_prog.c langm@iris.rhodes.edu:./my_prog.c
If I wanted to copy a directory name notes/ from my home directory on iris to my local computer, it would look like this (note the -r flag for recursive copy of a directory):
$ scp -r langm@iris.rhodes.edu:./notes ./notes
You can use a graphical program if you prefer. The recommended software page lists some.