Generate sitemap XML via BASH withwget. Based on https://www.lostsaloon.com/technology/how-to-create-an-xml-sitemap-using-wget-and-shell-script/

generate-sitemap-xml.sh

#!/bin/bash
cd /tmp
echo "Wget $1"
wget --spider --recursive --level=3 --no-verbose --output-file=sitemap.txt $1
echo "Grep URLs"
grep -i URL /tmp/sitemap.txt | awk -F 'URL:' '{print $2}' | awk '{$1=$1};1' | awk '{print $1}' | sort -u | sed '/^$/d' > /tmp/sitemap-urls.txt
header='<?xml version="1.0" encoding="UTF-8"?><urlset
      xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9
            http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">'
echo $header > /tmp/sitemap.xml
while read url; do
  case "$url" in
  http:* | https:*)
    echo '<url><loc>'$url'</loc></url>' >> sitemap.xml
    ;;
  *)
    ;;
 esac
done < /tmp/sitemap-urls.txt
echo "</urlset>" >> sitemap.xml