diff --git a/.bin/generate-environment-identifiers-dict.sh b/.bin/generate-environment-identifiers-dict.sh
new file mode 100644
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+++ b/.bin/generate-environment-identifiers-dict.sh
@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+# Script to build a list of of environment identifiers based on sub domain names.
+## References:
+# See https://blog.majestic.com/development/alexa-top-1-million-sites-retired-heres-majestic-million/
+# See https://github.com/danielmiessler/SecLists/issues/654
+# See https://github.com/danielmiessler/SecLists/pull/671
+## Requires jq
+#
+# Add more top level domain in the expression below
+TLD_WANTED_EXPR="\.(lu|be)$"
+#
+echo "[+] Download Majestic CSV file..."
+wget -O majestic.csv https://downloads.majestic.com/majestic_million.csv
+echo "[+] Extract wanted domains..."
+cat majestic.csv | cut -d',' -f3 | grep -E $TLD_WANTED_EXPR > domains.txt
+wc -l domains.txt
+echo "[+] Extract sub domains via Certificate Transparency logs (https://crt.sh)..."
+while IFS= read -r line
+do
+	printf "\rDomain: %-40s" "$line"
+	curl -sk "https://crt.sh/?q=$line&output=json" | jq -r ".[].name_value" | cut -d'.' -f1 1>> subdomains.txt 2>/dev/null
+done < domains.txt
+cat subdomains.txt | sort -u > subdomains.tmp
+mv subdomains.tmp subdomains.txt 
+wc -l subdomains.txt
+echo "[+] Extract environment like sub domains..."
+grep -Ei "^(de|dv|ts|te|in|st|ho|pr|pp)" subdomains.txt > env-like-subdomains.txt
+echo "[i] Manually review the generated file 'env-like-subdomains.txt' for accurate content."
+wc -l env-like-subdomains.txt