Creating a tmux Session on the Server Connected via SSH for Long-Running Scripts

When you have a script that will take a long time to run on a server, it's beneficial to use tmux to keep the process running even if you disconnect from the server. Here's a step-by-step guide on how to do it:

Step 1: Connect to Your Server

Use SSH to connect to your server.

ssh user@your-server.com

Remember the machine you just got connected to (e.g. app01). The tmux session lives only on that machine, so if you reconnect later make sure you are on the same one.

Step 2: Start a tmux Session

Start a new tmux session. You can name the session for easy identification.

tmux new -s script

Step 3: Run Your Script

cd /path/to/your/project
# Option A: run a script/command directly
./your-long-running-script.sh

# Option B: open an interactive runtime console, then execute the script there
bundle exec rails c -e production
# or (example)
python manage.py shell

Once inside the console, paste/run the script you need. Keep small progress logs (e.g. puts in Ruby, print in Python) so you can verify it is moving forward.

Step 4: Detach from the tmux Session

Detach from the tmux session while leaving your script running in the background.

Ctrl + b, then d

Press Ctrl and b together, then release both keys and press d. This detaches the session.

Step 5: Reattach to the tmux Session

To check on the progress of your script or to reattach to the session at any time, first connect to the server (make sure you are on the correct machine) and list all active tmux sessions:

tmux ls

Your session script should appear in the list.

Reattach to the session:

tmux attach -t script

Step 6: Kill a tmux Session

Once your script has finished running and you no longer need the tmux session, you can kill it. If you are already attached, just use Ctrl + d as you would normally. If you are detached and want to kill it remotely, use:

tmux kill-session -t script