diff --git a/bin/main b/bin/main
index 2ec0340..392c605 100755
Binary files a/bin/main and b/bin/main differ
diff --git a/obj/main.o b/obj/main.o
index 16cfb27..d850670 100644
Binary files a/obj/main.o and b/obj/main.o differ
diff --git a/obj/options.o b/obj/options.o
index bcbf6b3..68ad361 100644
Binary files a/obj/options.o and b/obj/options.o differ
diff --git a/obj/util.o b/obj/util.o
index 5d82e7d..b2c0c1b 100644
Binary files a/obj/util.o and b/obj/util.o differ
diff --git a/src/main.cpp b/src/main.cpp
index ed68379..63d9f94 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -88,6 +88,15 @@ int main(int argc, char *argv[])
     
     std::cout << "there are " << valid_words.size() << " valid words.\n";
 
+    // test for a regex filter
+    /*
+    if (Options["regex"]) {
+        // there is a regex option
+        std::cout << "main(): regex option value: " << Options["regex"] << ".\n";
+    }
+    */
+
+    // display the inputted command line, for reference
     std::cout << "You entered: ";
     for ( int i = 0 ; i<= argc ; i++ ) {
         std::cout << argv[i] << " ";
diff --git a/src/options.cpp b/src/options.cpp
index 41ec432..6e154a5 100755
--- a/src/options.cpp
+++ b/src/options.cpp
@@ -143,8 +143,7 @@ void Option_Switch( int count, char** arg, int* j, std::unordered_map<std::strin
 
         // test if the next argument would overflow argv
         if ( *j+1 < count ) {
-            // there are more args, which could means letters submitted to -e.
-            // test if the next arg is an option
+            // there is at least one more argv element. Test if the next arg is an option
             if ( ! isOption( arg[*j+1] ) ) {
                 // letters were submitted to -e, so ingest them
                 // std::cout << "Option_Switch():" << arg[*j] << " returned value " << arg[*j+1] << ".\n";
@@ -155,6 +154,34 @@ void Option_Switch( int count, char** arg, int* j, std::unordered_map<std::strin
             }
         }
     }
+    else if ( strcmp(arg[*j],"-x") == 0 ){
+        // this is the regex option, that filters the valid words by matching this user-inputted regex. 
+        std::cout << "Option_Switch(): Option \"-x\" detected.\n";
+
+        // test if the next argument would overflow argv
+        if ( *j+1 >= count ) {
+            // thia means now value was submitted with the -x option. That's an error/
+            std::cout << "Option_Switch(): \"-x\" option requires a regex, exiting.\n";
+            show_usage("");
+            exit(1);
+        }
+
+        // test if the next arg is an option
+        if ( isOption( arg[*j+1] ) ) {
+            // this is also an error, because if the next argv element is an option, it again 
+            // means no regex was submitted with -x. That's an error.
+            std::cout << "Option_Switch(): \"-x\" option requires a regex, exiting.\n";
+            show_usage("");
+            exit(1);
+        }
+
+        std::cout << "Option_Switch: " << arg[*j] << " returned value " << arg[*j+1] << ".\n";
+
+        ( *n ).emplace( "regex", arg[*j+1] );
+        // increment j becaue the j+1 arg has already been used. Don't want 
+        // to use it in the for loop twice
+        *j += 1;
+    }
     else if ( strcmp(arg[*j],"-b") == 0 ) {
         // std::cout << "Option_Switch(): option b loop index value is " << *j << "\n";
         ( *n ).insert({"blanks","blank1"});
diff --git a/src/util.cpp b/src/util.cpp
index c8f6a11..3d0f58a 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -51,7 +51,6 @@ std::set<std::string> WWF::get_dictionary() {
 
 }
 
-
 struct comp {
     template <typename T>
  
@@ -103,19 +102,13 @@ std::set<std::pair<std::string,int>> WWF::Words_Sorted(
 //    std::cout << "About to test regex.\n";
 
     options.count("regex") == 1 ? isRegex = true : isRegex = false;
-
-    if ( options.count("regex") == 1 ) {
-        isRegex = 1;
-        // this casts the std::string input to a std::regex
-        regex_input = std::regex( options.at("regex") );
-    }
-
-//    std::cout << "Tested regex.\n";
+    // std::cout << "Util::Words_Sorted(): isRegex = " << isRegex << "\n";
 
     for (auto& it : S) {
         // this prints the valid, sorted words to the screen
         std::cout << it.first << ' ' << it.second << "\n";
         if ( isRegex ) {
+            regex_input = std::regex( options.at("regex") );
             if ( std::regex_search(it.first, regex_input ) ) {
                 // long-ass process to cast an int to a string
                 std::stringstream stream;
@@ -127,17 +120,22 @@ std::set<std::pair<std::string,int>> WWF::Words_Sorted(
             }
         }
     }
-    if ( regex_matches.size() ) {
-        std::cout   << regex_matches.size() 
-                    << " words match your regex \"" 
-                    << options.at("regex")
-                    << "\"\n";
-    
-        for ( auto elem : regex_matches ) {
-            std::cout << elem << "\n";
+
+    if ( isRegex ) {
+
+        if ( regex_matches.size() ) {
+            std::cout   << regex_matches.size() 
+                        << " words match your regex \"" 
+                        << options.at("regex")
+                        << "\"\n";
+            for ( auto elem : regex_matches ) {
+                std::cout << elem << "\n";
+            }
+        }
+        else {
+            std::cout << "Words_Sorted(): no words match \"" << options.at("regex") << "\"\n";
         }
     }
-
     return return_value;
 } // end Words_Sorted()