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Laptop Lid Behavior When Powered On (Ubuntu 18.04)

This guide configures your laptop running Ubuntu 18.04.3 to do nothing when the lid closes while on AC power but suspend when on battery. Great for using your ThinkPad X1 Carbon or other laptops as a docked workstation without auto-sleep.

1. Set Default Lid Behavior

Edit /etc/systemd/logind.conf and set the lid switch behavior:

sudo nano /etc/systemd/logind.conf

Add or edit these lines:

HandleLidSwitch=ignore
HandleLidSwitchDocked=ignore

Restart logind:

sudo systemctl restart systemd-logind

2. Create the Script

This script dynamically changes the lid behavior depending on power state:

sudo nano /usr/local/bin/lid-power-handler.sh

#!/bin/bash
LID_CONF="/etc/systemd/logind.conf"

apply_setting() {
    local setting=$1
    sudo sed -i "s/^HandleLidSwitch=.*/HandleLidSwitch=$setting/" $LID_CONF
    systemd-inhibit --what=handle-lid-switch --why="AC power override" --mode=block sleep 0
}

while true; do
    if on_ac_power; then
        apply_setting "ignore"
    else
        apply_setting "suspend"
    fi
    sleep 10
done

Make it executable:

sudo chmod +x /usr/local/bin/lid-power-handler.sh

3. Create a Systemd Service

Set up a service so this script runs in the background:

sudo nano /etc/systemd/system/lid-power-handler.service

[Unit]
Description=Dynamic Lid Close Behavior Based on Power State
After=multi-user.target

[Service]
ExecStart=/usr/local/bin/lid-power-handler.sh
Restart=always

[Install]
WantedBy=multi-user.target

4. Enable and Start the Service

Reload systemd and start the new service:

sudo systemctl daemon-reload
sudo systemctl enable --now lid-power-handler.service

Test it:
- Plugged in → Lid close = does nothing.
- On battery → Lid close = suspends.