Tmux Quick Reference Guide

1. Install & Start Tmux

sudo apt install tmux
tmux

• Starts a new tmux session.
• Even if SSH disconnects, the session keeps running in the background.

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2. Basic Workflow

• Run all upgrade commands inside tmux.
• If SSH disconnects, log back in and reattach:

tmux attach

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3. Common Commands

Action	Keys
Detach from session (leave it running)	Ctrl+b then d
List sessions	tmux ls
Attach to last session	tmux attach
Attach to specific session	tmux attach -t SESSION_NAME
Create new named session	tmux new -s mysession
Kill current session	type exit
Kill a session from outside	tmux kill-session -t SESSION_NAME
Rename current session	Ctrl+b then $
Scroll output mode	Ctrl+b then [ (exit with q)
Split window vertically	Ctrl+b then %
Split window horizontally	Ctrl+b then "
Switch panes	Ctrl+b then Arrow keys

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4. Best Practice for Server Upgrades

1. Start a named tmux session:

tmux new -s upgrade

2. Run your upgrade commands inside:

sudo apt update
sudo apt upgrade --without-new-pkgs
sudo apt full-upgrade

3. Detach if needed:
   • Press Ctrl+b then d
4. Reattach later:

ssh user@server
tmux attach -t upgrade

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5. Tips

• Name sessions for easy reattachment.
• Multiple sessions can run simultaneously.
• Detaching and reattaching resets your layout view.