dead_switch.sh

dead_switch.sh

#!/bin/bash

# Add this script to crontab:
# `sudo printf "33 3\t* * *\troot\t/etc/dead_switch.sh" >> /etc/crontab`

# Dead Switch configuration
your_email=""
server_username=""
warning_time=$((3600 * 24 * 14))
trigger_time=$((3600 * 24 * 28))

# Emails
warning_email_title="[WARNING] Dead Switch"
warning_email_body="Server feels alone, please log in."
critical_email_title="[CRITICAL] Dead Swtich"
critical_email_body=$(cat <<EOF
Log in immediately.
The dead switch will be triggered within 24 hours.
EOF
)
farewell_email_title="Farewell"
farewell_email_body="It's been nice."

last_login_time=$(last -1 -R "$server_username" --time-format iso |            \
awk '{print $3}' | date -d "$1" +"%s")
current_time=$(date +%s)
if [[ $current_time -gt $((last_login_time + warning_time)) ]]; then
    send_mail "$your_email" "$warning_email_title" "$warning_email_body"
fi
if [[ $current_time -gt $((last_login_time + trigger_time - 86400)) ]]; then
    send_mail "$your_email" "$critical_email_title" "$critical_email_body"
fi
if [[ $current_time -gt $((last_login_time + trigger_time)) ]]; then
    send_mail "$your_email" "$farewell_email_title" "$farewell_email_body"
    # Here you do your stuff. Example:
    # send_mail "[email protected]" "[IMPORTANT] Dead Switch"                \
    # "Anon is dead.\nHis last words: good luck lmao."
    # srm -rf /
    sed -i '/dead_switch/s/^/#/g' /etc/crontab
fi

send_mail is defined here: https://gist.github.com/hydrastro/5ccfc0dc87a8bb3c5ec9062a3cba5bf6

sed -i '/dead_switch/s/^/#/g' /etc/crontab comments out the crontab entry for the dead switch, so it doesn't run twice.