cse15l-lab-reports

CSE 15L Lab Reports

1. Installing VScode

Download VScode from the website: https://code.visualstudio.com

Remember to download the right version, like OSX (for Macs) and Windows (for PCs).
After you successfully install VScode, it should look like this:

2. Remotely Connecting

First, install the program called OpenSSH from this link: https://docs.microsoft.com/en-us/windows-server/administration/openssh/openssh_install_firstuse

Secondly, look up your CSE 15L SSH account from here: https://sdacs.ucsd.edu/~icc/index.php

Then, open a a terminal in VSCode by using “‘Ctrl’ + ‘shift’ + ‘`’” or the Terminal → New Terminal menu option. Type the following command:

$ ssh cs15lwi22zz@ieng6.ucsd.edu

After you see a window like this:

⤇ ssh cs15lwi22zz@ieng6.ucsd.edu The authenticity of host 'ieng6.ucsd.edu (128.54.70.227)' can't be established. RSA key fingerprint is SHA256:ksruYwhnYH+sySHnHAtLUHngrPEyZTDl/1x99wUQcec. Are you sure you want to continue connecting (yes/no/[fingerprint])?

Type yes and press enter. You will see a window like following:

3. Trying Some Commands

There are many commands you can try in the terminal, here are some examples:
cd This takes you back home.
ls -lat This lists all files (including hidden ones) and permissions of these files. The files are sort by time and date.
ls -a This shows the hidden files.
mkdir This makes a new directory.

If you want to log out of the remote server in your terminal, you can use:
Ctrl-D
The command exit

Below is an example terminal command:

4. Moving Files with scp

To move files from the client over to SSH (the server), you can use the command scp. Create a file on your computer called WhereAmI.java and put the following contents into it:

class WhereAmI {
  public static void main(String[] args) {
    System.out.println(System.getProperty("os.name"));
    System.out.println(System.getProperty("user.name"));
    System.out.println(System.getProperty("user.home"));
    System.out.println(System.getProperty("user.dir"));
  }
}

Then, go to the terminal from the directory where you made this file and run this command (replace zz with your username):

scp WhereAmI.java cs15lwi22zz@ieng6.ucsd.edu:~/

Your file is now moved to SSH! After entering ls, you should be able to see:

5. Setting an SSH Key

In order to not enter your password to log in every time, you can use an SSH key, and here is how it works:

On your computer (client), type the command: $ ssh-keygen

Then this will show up:

Generating public/private rsa key pair.
Enter file in which to save the key (/Users/joe/.ssh/id_rsa): /Users/joe/.ssh/id_rsa
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /Users/joe/.ssh/id_rsa.
Your public key has been saved in /Users/joe/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:jZaZH6fI8E2I1D35hnvGeBePQ4ELOf2Ge+G0XknoXp0 joe@Joes-Mac-mini.local
The key's randomart image is:
+---[RSA 3072]----+
|                 |
|       . . + .   |
|      . . B o .  |
|     . . B * +.. |
|      o S = *.B. |
|       = = O.*.*+|
|        + * *.BE+|
|           +.+.o |
|             ..  |
+----[SHA256]-----+

If you are using Windows, there are a few more ssh-add steps, follow the instructions here: https://docs.microsoft.com/en-us/windows-server/administration/openssh/openssh_keymanagement#user-key-generation

Now we need to copy the public key to the .ssh directory of your user account on the server. After logging into your account, on the server, enter mkdir .ssh. Then, log out and follow the steps:

$ ssh cs15lwi22zz@ieng6.ucsd.edu
<Enter Password>
# now on server
$ mkdir .ssh
$ <logout>
# back on client
$ scp /Users/joe/.ssh/id_rsa.pub cs15lwi22@ieng6.ucsd.edu:~/.ssh/authorized_keys
# You use your username and the path you saw in the command above

After this step you should be able to log in withour entering your password:

6. Optimizing Remote Running

You can write a command at the end an ssh command to directly run it on the remote server, then immediately exit. $ ssh cs15lwi22@ieng6.ucsd.edu "ls"

You can also run multiple commands on the same line. $ cp WhereAmI.java OtherMain.java; javac OtherMain.java; java WhereAmI

The example is shown below. The number of total keystrokes is 7.