Linux

A collection of notes on using Linux systems, in particular Ubuntu.

SSH

SSH Keys

Generate an ssh-key for every client

ssh-keygen -t ed25519 -a 100 [-C "comment your client name"] [-f output_path]

Some older software such as Solid file explorer require RSA keys in PEM key format

ssh-keygen -t rsa -b 4096 -a 100 -m PEM [-C "comment your client name"] [-f output_path]

You can also convert existing keys to PEM format

ssh-keygen -p -m PEM [-C "comment your client name"] [-f output_path]

Manage ssh keys

# On the client
ssh-copy-id [email protected]

# On the server
vim ~/.ssh/authorized_keys

Notes:

• According to this you should avoid using ECDSA and DSA keys.

Port Forwarding

Also: SSH Tunneling, SSH Proxy, SSH Reverse Proxy
If you need to access a port on the remote computer, you can use the -L option to forward ports from the remote to the local machine.

ssh -L <localport>:localhost:<remoteport> <remoteurl>
# E.g. ssh -L 8080:localhost:80 [email protected]

You can also do the reverse, giving the remote access to a local port using -R

ssh -R <localport>:host:<remoteport> <remoteurl>
# E.g. ssh -R 8080:localhost:80 [email protected]

Nvidia

Switching between Nvidia and Intel

Reference
Make sure the Nvidia graphics drivers are installed. Then you can select between Nvidia and Intel GPUs using the Nvidia X Server Settings application nvidia-settings. Alternatively, you can use the following commands in the terminal.
To switch to the Nvidia GPU:

sudo prime-select nvidia

To switch back to the Intel GPU:

sudo prime-select intel

prime-select query will print either nvidia or intel to stdout.