Update system timezone based on IP geolocation, established under Linux Munt 18.3.

tzupdate.sh

#!/bin/bash

# crontab:
# */10 * * * * tzupdate.sh
# @reboot doesn't fit because of network connection delay.

# Get external IP
IP=$(curl ifconfig.me)

# Request to geolocation web service (https://ipgeolocation.io/documentation/timezone-api.html).
REQ="https://api.ipgeolocation.io/timezone?apiKey=$GEOTOKEN&ip=$IP"

data=$(curl $REQ)

# Naively parse responce - under assumption of uniqueness of "timezone" field in, which accords with docs.
tz=$(echo $data | grep -Po "(?<=\"timezone\":\")[^\"]*?(?=\")")

# Set system timezone.
timedatectl set-timezone "$tz"