lab-report-1-week-2.md

Week 2 Lab Report

Remote Access for Mac OS

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Installing VS Code

Go to VS Code's website and click download.

Extract the downloaded .zip file and move the application to /Applications/.

Open the application and you should be able to start working!

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Remotely Connecting

Use UCSD's Account Lookup tool to find your CSE15L remote access login information.

Your username should be of the form cs15lsp22, followed by three letters. Make sure to set/find your password.

Open a new terminal by navigating Terminal → New Terminal.

Enter the command $ ssh cs15lsp22[ ]@ieng6.ucsd.edu (where the blank is filled in with your username's specific letters) into the terminal. Continue if asked, and then enter your password when prompted.

You are now successfully remotely logged in!

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Trying Out Commands

There are plenty of commands you can try to run from your terminal. Here are some examples:

• cd <destination> (move from one directory to another)
• ls <destination> (list the contents of a directory, or the current directory if not specified)
• pwd (print the absolute path of the current working directory)
• cp <source> <destination> (copy a file)
• cat <source> (print out the contents of a file)
• mv <source> <destination> (move a file)
• mv <source> <new name> (rename a file)
• mkdir <name> (create a new directory)

Remember: When logged in remotely, commands run from the remote server instead of your local client.

Remember: You can use modifiers like ls -a or ls -l to modify the behavior of commands, or ls -la to do both at the same time.

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Moving Files with scp

Inevitably, you will need to move files from your local client to the remote server. To do this, you use the command scp. The syntax is as follows, and is run from your local client:

scp <source> <destination>

In practice, this may look like

scp TestFile.txt [email protected]:~/

If prompted, enter your password.

Remember: For the destination of the file, in this case, [email protected] designates the remote account we are accessing, while :~/ designates that we are transfering the file to the home directory.

After successfully running the command, you should be met with a readout displaying the name of the transferred file, and statistics on its transfer.

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Setting an SSH Key

SSH keys allow you to skip the step of having to enter your password every time you use ssh or scp commands. To set up your keys, do as follows:

1. On the local client, run the command ssh-keygen to generate your public and private keys. When prompted to enter a file or passphrase, simply click return.

2. ssh into the remote server and run the command mkdir .ssh to create a new directory. Then exit.

3. From your local client again, run the command scp /Users/<username>/.ssh/id_rsa.pub [email protected]:~/.ssh/authorized_keys to copy the public key to the remote server. Your <username> is the username on your local client, i.e. /Users/lukesheltraw/. Remember to replace abc with your remote server's three letters.

Try running scp and ssh now. You shouldn't need to enter a password!

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Optimizing Remote Running

A very common use case of a remote server is copying a file from your local client to the remote server, compiling it, and then running it. In general, when there exists a series of commands that are run often, it can be useful to find faster ways to enter them.

Here are a few principles we can use to do so:

• Distinct commands can be combined onto a single line by separating them with semicolons (;).
• Single commands can be run from the remote server following the format ssh <server> <command>.
• Multiple arguments / commands can be connected with quotes ("").

For instance, to transfer a Java file to the remote server, compile it, and then run it, we might use a single command that looks like this:

scp Example.java [email protected]:~/ ; ssh [email protected] "javac Example.java ; java Example"

Remember: You can use the up and down keys to locate previously used commands quickly.

This is what such a command would look like running a Java file that prints out the phrase "Hello World!". Note that this file is run from the remote server, not the local client.