Script to Shutdown Idle linux server

sshIdleShutdown.service

[Unit]
Description=SSH idle shutdown
After=ssh.service


[Service]
ExecStart=/usr/bin/sshIdleShutdown.sh
Restart=on-failure
RestartSec=5s

[Install]
WantedBy=multi-user.target

sshIdleShutdown.sh

#!/usr/bin/env bash
# create a script to shutdown the server if there is no active ssh connection
# for 30 minutes this script will be manged as system service

# save this script in /usr/bin/sshIdleShutdown.sh

# create service file in /usr/lib/systemd/system/sshIdleShutdown.service

# Install and enable service
# sudo systemctl daemon reload && sudo systemctl enable sshIdleShutdown.service

# start the service
# sudo systemctl start sshIdleShutdown.service

timeToShutdown=30
while true; do
    # check if there is an active ssh connection
    if [[ $(pgrep -f "sshd: [^@]*@") ]]; then
        # there is an active ssh connection
        # reset the counter
        echo 0 >/tmp/ssh_counter
        echo "active ssh connection; counter reset"
    else
        # there is no active ssh connection
        # increment the counter
        counter=$(cat /tmp/ssh_counter)
        counter=$((counter + 1))
        echo $counter >/tmp/ssh_counter
        echo "no active ssh connection; counter incremented to $counter"
    fi

    # check if the counter is greater than 30
    if [[ $(cat /tmp/ssh_counter) -gt $timeToShutdown ]]; then
        # the counter is greater than 30
        # shutdown the server
        sudo init 0
    fi
    sleep 60
done