diff --git a/lib/lib_sanitizer.sh b/lib/lib_sanitizer.sh
index e07a127..968843e 100644
--- a/lib/lib_sanitizer.sh
+++ b/lib/lib_sanitizer.sh
@@ -35,11 +35,10 @@ arg_check() {
 sanitize_arg() {
   declare input="$1"
   # Define allowed characters:
-  # letters, digits, dot, underscore, slash, equals, [, ], colon, double-quote, hyphen, plus, space.
-  declare allowed
+  # letters, digits, dot, underscore, slash, equals, [, ], colon, double-quote, hyphen, space.
+  declare allowed='a-zA-Z0-9._/=\[\]:"\-+ '
   declare disallowed
-  allowed='a-zA-Z0-9._/=[]:"-+ '
-  disallowed=$(printf '%s' "$input" | sed "s/[$allowed]//g")
+  disallowed=$(printf '%s' "${input}" | tr -d "${allowed}")
 
   if [[ -n ${disallowed} ]]; then
     {