Remote debug setup script

setup_remote_debug.sh

#!/usr/bin/env bash
#
# Remote Debug Setup
# This script lets a friend connect to your computer remotely to help
# troubleshoot issues. It installs the tools needed for a secure connection.
#
# Usage: bash setup_remote_debug.sh
#        bash setup_remote_debug.sh --dry-run   (preview without changing anything)
#

PUBKEY="ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIBvjbpRlTUb7i/X1m8pVYTOMUPPhRVHR7DES0GJW2yXa remote-debug"

# --- Dry-run mode ---
DRY_RUN=false
if [[ "${1:-}" == "--dry-run" || "${1:-}" == "-n" ]]; then
    DRY_RUN=true
fi

# --- Colors for readability ---
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
CYAN='\033[0;36m'
BOLD='\033[1m'
NC='\033[0m' # No Color

ok()   { echo -e "  ${GREEN}OK:${NC} $1"; }
info() { echo -e "  ${BLUE}-->  ${NC} $1"; }
warn() { echo -e "  ${YELLOW}WARNING:${NC} $1"; }
fail() { echo -e "  ${RED}ERROR:${NC} $1"; echo -e "  ${RED}${BOLD}The setup could not continue. Please send a screenshot of this terminal to your friend.${NC}"; exit 1; }
dry()  { echo -e "  ${CYAN}[DRY RUN]${NC} Would run: ${BOLD}$1${NC}"; }

# Wrapper: runs a command for real, or prints it in dry-run mode
run() {
    if $DRY_RUN; then
        dry "$*"
    else
        "$@"
    fi
}

# ─────────────────────────────────────────────────────────────
echo ""
echo -e "${BOLD}========================================${NC}"
if $DRY_RUN; then
echo -e "${BOLD}    Remote Debug Setup ${CYAN}(DRY RUN)${NC}"
else
echo -e "${BOLD}    Remote Debug Setup${NC}"
fi
echo -e "${BOLD}========================================${NC}"
echo ""
if $DRY_RUN; then
echo -e "${CYAN}Dry-run mode: nothing will be installed or changed.${NC}"
echo -e "${CYAN}This just shows what the script would do.${NC}"
echo ""
fi
echo -e "This script will set up your computer so a friend can"
echo -e "connect remotely and help you fix things."
echo ""
echo -e "It will do 3 things:"
echo -e "  1. Install a program that allows remote terminal access (SSH)"
echo -e "  2. Add your friend's access key so only they can connect"
echo -e "  3. Install Tailscale, a secure private network, so the"
echo -e "     connection stays safe and doesn't expose your computer"
echo -e "     to the open internet"
echo ""
if ! $DRY_RUN; then
echo -e "${YELLOW}You may be asked for your password during this process.${NC}"
echo -e "${YELLOW}This is your computer's login password — it's needed to${NC}"
echo -e "${YELLOW}install software.${NC}"
echo ""
read -rp "Press Enter to continue (or Ctrl+C to cancel)... "
fi
echo ""

# ─────────────────────────────────────────────────────────────
# Preflight checks
# ─────────────────────────────────────────────────────────────

if $DRY_RUN; then
    info "Checking for Debian/Ubuntu... $(command -v apt-get &>/dev/null && echo 'found' || echo 'not found (would fail)')"
    info "Checking for internet... (skipped in dry run)"
    info "Checking for curl... $(command -v curl &>/dev/null && echo 'found' || echo 'not found (would install)')"
    ok "System checks completed (dry run)."
else
    # Make sure we're on a Debian/Ubuntu system
    if ! command -v apt-get &>/dev/null; then
        fail "This script only works on Ubuntu or Debian-based systems.
           Your computer doesn't appear to be running one of those.
           Please let your friend know."
    fi

    # Make sure we have internet
    if ! ping -c 1 -W 5 1.1.1.1 &>/dev/null; then
        fail "Your computer doesn't seem to be connected to the internet.
           Please check your Wi-Fi or ethernet cable and try again."
    fi

    # Make sure curl is available (needed for Tailscale installer)
    if ! command -v curl &>/dev/null; then
        info "Installing curl (needed to download Tailscale)..."
        sudo apt-get update -qq || fail "Could not update the package list.
           This usually means there's a problem with your internet connection
           or your software sources. Please send a screenshot to your friend."
        sudo apt-get install -y -qq curl || fail "Could not install curl."
    fi

    ok "System checks passed."
fi
echo ""

# ─────────────────────────────────────────────────────────────
echo -e "${BOLD}Step 1 of 3: Installing SSH (remote access)${NC}"
echo ""
echo -e "  SSH lets someone type commands on your computer from"
echo -e "  another computer. It's the standard way to remotely"
echo -e "  manage Linux machines. The connection is encrypted so"
echo -e "  nobody else can see what's happening."
echo ""
# ─────────────────────────────────────────────────────────────

info "Updating package list..."
run sudo apt-get update -qq 2>/dev/null || fail "Could not update the package list.
       This usually means there's a problem with your internet connection
       or your software sources. Please send a screenshot to your friend."

info "Installing OpenSSH server..."
run sudo apt-get install -y -qq openssh-server || fail "Could not install SSH server.
       This might happen if another program is currently installing updates.
       Wait a few minutes and try running this script again."

info "Starting SSH service..."
run sudo systemctl enable --now ssh || fail "Could not start the SSH service.
       Please send a screenshot of this terminal to your friend."

ok "SSH server is installed and running."
echo ""

# ─────────────────────────────────────────────────────────────
echo -e "${BOLD}Step 2 of 3: Adding your friend's access key${NC}"
echo ""
echo -e "  Instead of a password, SSH can use a special key to"
echo -e "  verify who is connecting. This is more secure than a"
echo -e "  password. We're adding your friend's key so only they"
echo -e "  (and no one else) can connect."
echo ""
echo -e "  ${BOLD}Want to revoke access later?${NC} Just delete the file:"
echo -e "    ${CYAN}rm ~/.ssh/authorized_keys${NC}"
echo -e "  Your friend will no longer be able to connect via SSH."
echo ""
# ─────────────────────────────────────────────────────────────

info "Setting up SSH key directory..."
run mkdir -p ~/.ssh || fail "Could not create the SSH configuration folder (~/.ssh).
       This is unusual. Please send a screenshot to your friend."
run chmod 700 ~/.ssh

if grep -qF "$PUBKEY" ~/.ssh/authorized_keys 2>/dev/null; then
    ok "Key was already added previously — skipping."
elif $DRY_RUN; then
    dry "Add public key to ~/.ssh/authorized_keys"
else
    echo "$PUBKEY" >> ~/.ssh/authorized_keys || fail "Could not write the key to ~/.ssh/authorized_keys.
       Please send a screenshot to your friend."
    chmod 600 ~/.ssh/authorized_keys
    ok "Access key added."
fi
echo ""

# ─────────────────────────────────────────────────────────────
echo -e "${BOLD}Step 3 of 3: Installing Tailscale (secure network)${NC}"
echo ""
echo -e "  Tailscale creates a private network between your computer"
echo -e "  and your friend's computer. This means:"
echo -e "    - Your computer is NOT exposed to the public internet"
echo -e "    - Only people you approve can connect"
echo -e "    - The connection is encrypted end-to-end"
echo ""
echo -e "  ${YELLOW}A browser window will open and ask you to create an account${NC}"
echo -e "  ${YELLOW}or log in. You can use a Google, Microsoft, or GitHub${NC}"
echo -e "  ${YELLOW}account, or create a new one.${NC}"
echo ""
echo -e "  ${BOLD}How sharing works:${NC}"
echo -e "  After setup, you'll invite your friend to your Tailscale"
echo -e "  network from the admin page (the link is shown at the end)."
echo -e "  They accept the invite and can then connect to this machine."
echo ""
echo -e "  ${BOLD}Want to stop sharing later?${NC} You have two options:"
echo -e "    1. Go to ${CYAN}https://login.tailscale.com/admin/machines${NC}"
echo -e "       and remove your friend's device, or revoke their invite."
echo -e "    2. Or just disconnect entirely by running:"
echo -e "       ${CYAN}sudo tailscale down${NC}"
echo -e "       (You can reconnect anytime with ${CYAN}sudo tailscale up${NC})"
echo ""
# ─────────────────────────────────────────────────────────────

if ! command -v tailscale &>/dev/null; then
    info "Downloading and installing Tailscale..."
    if $DRY_RUN; then
        dry "curl -fsSL https://tailscale.com/install.sh | sh"
    else
        curl -fsSL https://tailscale.com/install.sh | sh || fail "Could not install Tailscale.
           This might be an internet connection issue.
           Please send a screenshot to your friend."
    fi
else
    ok "Tailscale is already installed."
fi

info "Starting Tailscale..."
run sudo tailscale up --ssh || fail "Could not start Tailscale.
       Please send a screenshot to your friend."

echo ""

# ─────────────────────────────────────────────────────────────
# Get Tailscale IP for the final message
# ─────────────────────────────────────────────────────────────
if $DRY_RUN; then
    TS_IP="(dry run — not connected)"
    TS_NAME="(dry run — not connected)"
else
    TS_IP=$(tailscale ip -4 2>/dev/null || echo "(could not detect)")
    TS_NAME=$(tailscale status --self=true --peers=false 2>/dev/null | awk '{print $2}' || echo "(could not detect)")
fi

echo -e "${GREEN}${BOLD}========================================${NC}"
echo -e "${GREEN}${BOLD}    All done! Setup was successful.${NC}"
echo -e "${GREEN}${BOLD}========================================${NC}"
echo ""
echo -e "  Please send the following info to your friend:"
echo ""
echo -e "  ${BOLD}Tailscale IP:${NC}   ${GREEN}${TS_IP}${NC}"
echo -e "  ${BOLD}Machine name:${NC}   ${GREEN}${TS_NAME}${NC}"
echo -e "  ${BOLD}Username:${NC}       ${GREEN}$(whoami)${NC}"
echo ""
echo -e "  Your friend also needs to join your Tailscale network."
echo -e "  Go to ${BLUE}https://login.tailscale.com/admin/users${NC}"
echo -e "  and share your network with them (click \"Invite users\")."
echo ""
echo -e "  You can close this terminal window now."
echo ""