Shell & Terminal

The command line is your primary interface to the AIRLab servers. This guide covers the basics of connecting, navigating, and managing your work through the shell.

Connecting via SSH

SSH (Secure Shell) creates an encrypted connection to the server. The server IPs are internal — ask your co-supervisor for them. To avoid typing raw IPs, add them to your system's hosts file as memorable aliases:

# AIRLab servers — replace with actual IPs from your co-supervisor
<WESTWORLD_IP>   westworld ww
<ELYSIUM_IP>     elysium   ely

# AIRLab servers — replace with actual IPs from your co-supervisor
<WESTWORLD_IP>   westworld ww
<ELYSIUM_IP>     elysium   ely

Note: You cannot directly overwrite this file with Notepad. Save the edited file anywhere on your desktop, then drag and drop it into C:\Windows\System32\drivers\etc\ to overwrite it (administrator permission required).

Then configure your SSH client to handle usernames and key selection automatically. Add the following to your SSH config file (create it if it doesn't exist):

# Westworld
Host ww westworld
  HostName westworld
  User lastname    <-- replace with your actual username on the server
  IdentityFile ~/.ssh/id_ed25519_airlab
  ServerAliveInterval 60
  ServerAliveCountMax 3

# Elysium
Host ely elysium
  HostName elysium
  User lastname    <-- replace with your actual username on the server
  IdentityFile ~/.ssh/id_ed25519_airlab
  ServerAliveInterval 60
  ServerAliveCountMax 3

# Westworld
Host ww westworld
  HostName westworld
  User lastname    <-- replace with your actual username on the server
  IdentityFile ~/.ssh/id_ed25519_airlab
  ServerAliveInterval 60
  ServerAliveCountMax 3

# Elysium
Host ely elysium
  HostName elysium
  User lastname    <-- replace with your actual username on the server
  IdentityFile ~/.ssh/id_ed25519_airlab
  ServerAliveInterval 60
  ServerAliveCountMax 3

With this in place, connecting to any server is just:

ssh ww      # westworld
ssh ely     # elysium

SSH Keys

Password authentication is convenient but weaker than key-based authentication. Set up an SSH key pair once and never type your password over the network again.

# 1. Generate a key pair (Ed25519 is the modern standard)
# The -C comment is optional but helps identify the key later
ssh-keygen -t ed25519 -C "airlab" -f ~/.ssh/id_ed25519_airlab

# 2. Copy the public key to every server you use
ssh-copy-id -i ~/.ssh/id_ed25519_airlab.pub lastname@<westworld_ip>
ssh-copy-id -i ~/.ssh/id_ed25519_airlab.pub lastname@<elysium_ip>

# 3. Test key login — no password prompt means it worked
ssh ww

# 1. Generate a key pair (Ed25519 is the modern standard)
# The -C comment is optional but helps identify the key later
ssh-keygen -t ed25519 -C "airlab" -f C:\Users\YourName\.ssh\id_ed25519_airlab

# 2. Windows does not have ssh-copy-id — use PowerShell instead
type C:\Users\YourName\.ssh\id_ed25519_airlab.pub | ssh lastname@<westworld_ip> "mkdir -p .ssh && cat >> .ssh/authorized_keys"
type C:\Users\YourName\.ssh\id_ed25519_airlab.pub | ssh lastname@<elysium_ip> "mkdir -p .ssh && cat >> .ssh/authorized_keys"

# 3. Test key login — no password prompt means it worked
ssh ww

GitHub on the Server

You will want to git clone and git push directly from the compute servers. The easiest way is to connect remotely with VSCode's Remote - SSH extension and use the built-in Git integration. More on that in the VS Code Integration section of the Docker guide.

Common Navigation & File Operations

Useful patterns

# Search command history
history | grep docker

# Count lines in a file
wc -l training.log

# Sort and unique a list
cat labels.txt | sort | uniq -c | sort -rn

# Extract a .tar.gz archive into a specific directory
tar -xzf dataset.tar.gz -C ~/storage_megaverse

Monitoring Resources

Before starting an experiment, always check that the resources you booked are actually free.

# CPU, RAM, and per-process stats (interactive — press q to quit)
htop

# Full GPU status: memory usage, utilisation, running processes
nvidia-smi

# Find who owns a process by surname
ps aux | grep surname

# Watch GPU utilisation live every 2 seconds
watch -n 2 nvidia-smi

Tmux — Persistent Terminal Sessions

Training a neural network can take hours or days. If your SSH connection drops — due to a network hiccup, a laptop going to sleep, or a VPN timeout — any process running directly in your terminal will be killed. tmux solves this by running your shell sessions on the server, completely independent of your connection. Detach, close your laptop, and reattach later to find everything exactly as you left it.

The key concept: Ctrl-b is the prefix — press it before every tmux shortcut, then release it before pressing the next key. A full cheat sheet is available here.

Quick start

# Create a named session (use a meaningful name — your project or experiment)
tmux new -s resnet_training

# Inside the session, start your experiment as normal
run-docker 0 0-8 "python train.py"

# Detach — your experiment keeps running on the server
# Press: Ctrl-b  then  d

# Later, reattach from any SSH session
tmux attach -t resnet_training

Sessions

Windows & Panes

A session can contain multiple windows (like browser tabs), and each window can be split into panes (side-by-side or stacked terminals).

Configuration

tmux is highly customizable. Create a ~/.tmux.conf file to set your preferred keybindings, status bar, colors, and more. Here's a sample config to get you started:

# Enable mouse support (click to select panes/windows, scroll history)
set -g mouse on

# Start window and pane numbering at 1
set -g base-index 1
set -g pane-base-index 1

# Increase scrollback history
set -g history-limit 50000

# Faster key repetition
set -sg escape-time 0

# Reload config with: Ctrl-b r
bind r source-file ~/.tmux.conf ; display-message "Config reloaded"

# Intuitive pane splitting (opens in current directory)
bind | split-window -h -c "#{pane_current_path}"
bind - split-window -v -c "#{pane_current_path}"

# Status bar
set -g status-right '%H:%M %d-%b'
set -g status-style 'bg=#102c53 fg=white'

# Reload config without restarting tmux
tmux source-file ~/.tmux.conf
# Or inside a session: Ctrl-b r