Update README.md

README.md

@@ -1692,18 +1692,20 @@ grep -HEronasi  '.{16}password.{,64}' .
 grep -r -F -- " PRIVATE KEY-----" .
 ```
 
-Find Subdomains in files:
+Find Subdomains or emails in files:
 ```bash
 find_subdomains() {
 	local d="${1}"
-	local rexf='[0-9a-z.-]{0,64}'"${d}"
-	local rex="$rexf"'([^a-z0-9]{1}|$)'
+	local rexf='[0-9a-zA-Z_.-]{0,64}'"${d}"
+	local rex="$rexf"'([^0-9a-zA-Z_]{1}|$)'
 	[ $# -le 0 ] && { echo -en >&2 "Extract sub-domains from all files (or stdin)\nUsage  : find_subdomains <apex-domain> <file>\nExample: find_subdomain \.com | anew"; return; }
 	shift 1
 	[ $# -le 0 ] && [ -t 0 ] && set -- .
 	command -v rg >/dev/null && { rg -oaIN --no-heading "$rex" "$@" | grep -Eo "$rexf"; return; }
 	grep -Eaohr "$rex" "$@" | grep -Eo "$rexf"
 }
+# find_subdomain foobar.com
+# find_subdomain @gmail.com
 ```
 
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