diff --git a/error_handling/errors1.rs b/error_handling/errors1.rs
index 843e6206..14ed574b 100644
--- a/error_handling/errors1.rs
+++ b/error_handling/errors1.rs
@@ -1,3 +1,4 @@
+// errors1.rs
 // This function refuses to generate text to be printed on a nametag if
 // you pass it an empty string. It'd be nicer if it explained what the problem
 // was, instead of just sometimes returning `None`. The 2nd test currently
diff --git a/error_handling/errors2.rs b/error_handling/errors2.rs
index a9cb9407..05824c13 100644
--- a/error_handling/errors2.rs
+++ b/error_handling/errors2.rs
@@ -1,3 +1,4 @@
+// errors2.rs
 // Say we're writing a game where you can buy items with tokens. All items cost
 // 5 tokens, and whenever you purchase items there is a processing fee of 1
 // token. A player of the game will type in how many items they want to buy,
diff --git a/error_handling/errors3.rs b/error_handling/errors3.rs
index 3ecffbc8..9b285e0b 100644
--- a/error_handling/errors3.rs
+++ b/error_handling/errors3.rs
@@ -1,3 +1,4 @@
+// errors3.rs
 // This is a program that is trying to use a completed version of the
 // `total_cost` function from the previous exercise. It's not working though--
 // we can't call the `try!` macro in the `main()` function! Why not?
diff --git a/error_handling/errorsn.rs b/error_handling/errorsn.rs
index e0d73dae..4fb2be30 100644
--- a/error_handling/errorsn.rs
+++ b/error_handling/errorsn.rs
@@ -1,3 +1,4 @@
+// errorsn.rs
 // This is a bigger error exercise than the previous ones!
 // You can do it!
 //
diff --git a/error_handling/option1.rs b/error_handling/option1.rs
index 5f961842..9cf0bc92 100644
--- a/error_handling/option1.rs
+++ b/error_handling/option1.rs
@@ -1,3 +1,4 @@
+// option1.rs
 // This example panics because the second time it calls `pop`, the `vec`
 // is empty, so `pop` returns `None`, and `unwrap` panics if it's called
 // on `None`. Handle this in a more graceful way than calling `unwrap`!
diff --git a/error_handling/result1.rs b/error_handling/result1.rs
index 7146d1ef..851ab451 100644
--- a/error_handling/result1.rs
+++ b/error_handling/result1.rs
@@ -1,3 +1,4 @@
+// result1.rs
 // Make this test pass! Scroll down for hints :)
 
 #[derive(PartialEq,Debug)]
diff --git a/ex1.rs b/ex1.rs
index b619495d..2366991f 100644
--- a/ex1.rs
+++ b/ex1.rs
@@ -1,3 +1,4 @@
+// ex1.rs
 // Make me compile!
 
 fn main() {
diff --git a/ex2.rs b/ex2.rs
index b0c7ca22..0fd714de 100644
--- a/ex2.rs
+++ b/ex2.rs
@@ -1,3 +1,4 @@
+// ex2.rs
 // Make me compile!
 
 fn something() -> String {
diff --git a/ex3.rs b/ex3.rs
index 242076fb..db27ad2c 100644
--- a/ex3.rs
+++ b/ex3.rs
@@ -1,3 +1,4 @@
+// ex3.rs
 // Make me compile!
 
 struct Foo {
diff --git a/ex4.rs b/ex4.rs
index d1ae563b..362a5570 100644
--- a/ex4.rs
+++ b/ex4.rs
@@ -1,3 +1,4 @@
+// ex4.rs
 // Make me compile!
 
 fn something() -> Result<i32, std::num::ParseIntError> {
diff --git a/ex5.rs b/ex5.rs
index 661b15ea..2eb8cfd6 100644
--- a/ex5.rs
+++ b/ex5.rs
@@ -1,3 +1,4 @@
+// ex5.rs
 // Make me compile!
 
 enum Reaction<'a> {
diff --git a/functions/functions1.rs b/functions/functions1.rs
index 30043632..396dd56f 100644
--- a/functions/functions1.rs
+++ b/functions/functions1.rs
@@ -1,3 +1,4 @@
+// functions1.rs
 // Make me compile! Scroll down for hints :)
 
 fn main() {
diff --git a/functions/functions2.rs b/functions/functions2.rs
index 97ed8f1d..1cf95c32 100644
--- a/functions/functions2.rs
+++ b/functions/functions2.rs
@@ -1,3 +1,4 @@
+// functions2.rs
 // Make me compile! Scroll down for hints :)
 
 fn main() {
diff --git a/functions/functions3.rs b/functions/functions3.rs
index 3dba67cc..b17543b3 100644
--- a/functions/functions3.rs
+++ b/functions/functions3.rs
@@ -1,3 +1,4 @@
+// functions3.rs
 // Make me compile! Scroll down for hints :)
 
 fn main() {
diff --git a/functions/functions4.rs b/functions/functions4.rs
index e514b84f..4da8d705 100644
--- a/functions/functions4.rs
+++ b/functions/functions4.rs
@@ -1,3 +1,4 @@
+// functions4.rs
 // Make me compile! Scroll down for hints :)
 
 // This store is having a sale where if the price is an even number, you get
diff --git a/functions/functions5.rs b/functions/functions5.rs
index a8d7cef0..f8fac5d2 100644
--- a/functions/functions5.rs
+++ b/functions/functions5.rs
@@ -1,3 +1,4 @@
+// functions5.rs
 // Make me compile! Scroll down for hints :)
 
 fn main() {
diff --git a/if/if1.rs b/if/if1.rs
index c2ea7345..51186577 100644
--- a/if/if1.rs
+++ b/if/if1.rs
@@ -1,3 +1,5 @@
+// if1.rs
+
 pub fn bigger(a: i32, b:i32) -> i32 {
     // Complete this function to return the bigger number!
     // Do not use:
diff --git a/macros/macros1.rs b/macros/macros1.rs
index 0e964ac5..a7c78a57 100644
--- a/macros/macros1.rs
+++ b/macros/macros1.rs
@@ -1,3 +1,4 @@
+// macros1.rs
 // Make me compile! Scroll down for hints :)
 
 macro_rules! my_macro {
diff --git a/macros/macros2.rs b/macros/macros2.rs
index bd5a82cf..bc2e56be 100644
--- a/macros/macros2.rs
+++ b/macros/macros2.rs
@@ -1,3 +1,4 @@
+// macros2.rs
 // Make me compile! Scroll down for hints :)
 
 fn main() {
diff --git a/macros/macros3.rs b/macros/macros3.rs
index 82814457..84c4308e 100644
--- a/macros/macros3.rs
+++ b/macros/macros3.rs
@@ -1,3 +1,4 @@
+// macros3.rs
 // Make me compile, without taking the macro out of the module! Scroll down for hints :)
 
 mod macros {
diff --git a/macros/macros4.rs b/macros/macros4.rs
index a15e1713..d844bb0d 100644
--- a/macros/macros4.rs
+++ b/macros/macros4.rs
@@ -1,3 +1,4 @@
+// macros4.rs
 // Make me compile! Scroll down for hints :)
 
 macro_rules! my_macro {
diff --git a/modules/modules1.rs b/modules/modules1.rs
index 71634950..0e092c5f 100644
--- a/modules/modules1.rs
+++ b/modules/modules1.rs
@@ -1,3 +1,4 @@
+// modules1.rs
 // Make me compile! Scroll down for hints :)
 
 mod sausage_factory {
diff --git a/modules/modules2.rs b/modules/modules2.rs
index e6d6f4c5..fefca904 100644
--- a/modules/modules2.rs
+++ b/modules/modules2.rs
@@ -1,3 +1,4 @@
+// modules2.rs
 // Make me compile! Scroll down for hints :)
 
 mod us_presidential_frontrunners {
diff --git a/move_semantics/move_semantics1.rs b/move_semantics/move_semantics1.rs
index a69ff90f..1f288731 100644
--- a/move_semantics/move_semantics1.rs
+++ b/move_semantics/move_semantics1.rs
@@ -1,3 +1,4 @@
+// move_semantics1.rs
 // Make me compile! Scroll down for hints :)
 
 pub fn main() {
diff --git a/move_semantics/move_semantics2.rs b/move_semantics/move_semantics2.rs
index 79c1c56d..6e676d14 100644
--- a/move_semantics/move_semantics2.rs
+++ b/move_semantics/move_semantics2.rs
@@ -1,3 +1,4 @@
+// move_semantics2.rs
 // Make me compile without changing line 9! Scroll down for hints :)
 
 pub fn main() {
diff --git a/move_semantics/move_semantics3.rs b/move_semantics/move_semantics3.rs
index fec370f9..7805d442 100644
--- a/move_semantics/move_semantics3.rs
+++ b/move_semantics/move_semantics3.rs
@@ -1,3 +1,4 @@
+// move_semantics3.rs
 // Make me compile without adding new lines-- just changing existing lines!
 // (no lines with multiple semicolons necessary!)
 // Scroll down for hints :)
diff --git a/move_semantics/move_semantics4.rs b/move_semantics/move_semantics4.rs
index 17df4267..2b1ed8aa 100644
--- a/move_semantics/move_semantics4.rs
+++ b/move_semantics/move_semantics4.rs
@@ -1,3 +1,4 @@
+// move_semantics4.rs
 // Refactor this code so that instead of having `vec0` and creating the vector
 // in `fn main`, we instead create it within `fn fill_vec` and transfer the
 // freshly created vector from fill_vec to its caller. Scroll for hints!
diff --git a/primitive_types/primitive_types1.rs b/primitive_types/primitive_types1.rs
index 95c06de2..c3d11fe8 100644
--- a/primitive_types/primitive_types1.rs
+++ b/primitive_types/primitive_types1.rs
@@ -1,3 +1,4 @@
+// primitive_types1.rs
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
diff --git a/primitive_types/primitive_types2.rs b/primitive_types/primitive_types2.rs
index a2c80f50..f5c8f87a 100644
--- a/primitive_types/primitive_types2.rs
+++ b/primitive_types/primitive_types2.rs
@@ -1,3 +1,4 @@
+// primitive_types2.rs
 // Fill in the rest of the line that has code missing!
 // No hints, there's no tricks, just get used to typing these :)
 
diff --git a/primitive_types/primitive_types3.rs b/primitive_types/primitive_types3.rs
index 3476ba66..a2f9b3b3 100644
--- a/primitive_types/primitive_types3.rs
+++ b/primitive_types/primitive_types3.rs
@@ -1,3 +1,4 @@
+// primitive_types3.rs
 // Create an array with at least 100 elements in it where the ??? is. 
 // Scroll down for hints!
 
diff --git a/primitive_types/primitive_types4.rs b/primitive_types/primitive_types4.rs
index b71cc330..c20b63bb 100644
--- a/primitive_types/primitive_types4.rs
+++ b/primitive_types/primitive_types4.rs
@@ -1,3 +1,4 @@
+// primitive_types4.rs
 // Get a slice out of Array a where the ??? is so that the `if` statement
 // returns true. Scroll down for hints!!
 
diff --git a/primitive_types/primitive_types5.rs b/primitive_types/primitive_types5.rs
index a34b750f..14c2fd26 100644
--- a/primitive_types/primitive_types5.rs
+++ b/primitive_types/primitive_types5.rs
@@ -1,3 +1,4 @@
+// primitive_types5.rs
 // Destructure the `cat` tuple so that the println will work.
 // Scroll down for hints!
 
diff --git a/primitive_types/primitive_types6.rs b/primitive_types/primitive_types6.rs
index 7ff9c675..d0166428 100644
--- a/primitive_types/primitive_types6.rs
+++ b/primitive_types/primitive_types6.rs
@@ -1,3 +1,4 @@
+// primitive_types6.rs
 // Use a tuple index to access the second element of `numbers`.
 // You can put this right into the `println!` where the ??? is.
 // Scroll down for hints!
diff --git a/standard_library_types/arc1.rs b/standard_library_types/arc1.rs
index a47dc19f..c744a108 100644
--- a/standard_library_types/arc1.rs
+++ b/standard_library_types/arc1.rs
@@ -1,3 +1,4 @@
+// arc1.rs
 // Make this code compile by filling in a value for `shared_numbers` where the
 // TODO comment is and creating an initial binding for `child_numbers`
 // somewhere. Try not to create any copies of the `numbers` Vec!
diff --git a/standard_library_types/iterator3.rs b/standard_library_types/iterator3.rs
index 0e0cb3e1..e973ac64 100644
--- a/standard_library_types/iterator3.rs
+++ b/standard_library_types/iterator3.rs
@@ -1,3 +1,4 @@
+// iterator3.rs
 // This is a bigger exercise than most of the others! You can do it!
 // Here is your mission, should you choose to accept it:
 // 1. Complete the divide function to get the first four tests to pass
diff --git a/standard_library_types/iterators4.rs b/standard_library_types/iterators4.rs
index e758bd17..13613a6c 100644
--- a/standard_library_types/iterators4.rs
+++ b/standard_library_types/iterators4.rs
@@ -1,3 +1,5 @@
+// iterators4.rs
+
 pub fn factorial(num: u64) -> u64 {
     // Complete this function to return factorial of num
     // Do not use:
diff --git a/strings/strings1.rs b/strings/strings1.rs
index 2bfbba2d..2e5088f9 100644
--- a/strings/strings1.rs
+++ b/strings/strings1.rs
@@ -1,3 +1,4 @@
+// strings1.rs
 // Make me compile without changing the function signature! Scroll down for hints :)
 
 fn main() {
diff --git a/strings/strings2.rs b/strings/strings2.rs
index 286a4f80..4239ff8f 100644
--- a/strings/strings2.rs
+++ b/strings/strings2.rs
@@ -1,3 +1,4 @@
+// strings2.rs
 // Make me compile without changing the function signature! Scroll down for hints :)
 
 fn main() {
diff --git a/strings/strings3.rs b/strings/strings3.rs
index a4e57754..b6f6a1ea 100644
--- a/strings/strings3.rs
+++ b/strings/strings3.rs
@@ -1,3 +1,4 @@
+// strings3.rs
 // Ok, here are a bunch of values-- some are `Strings`, some are `&strs`. Your
 // task is to call one of these two functions on each value depending on what
 // you think each value is. That is, add either `string_slice` or `string`
diff --git a/tests/tests1.rs b/tests/tests1.rs
index e189f937..959ed85e 100644
--- a/tests/tests1.rs
+++ b/tests/tests1.rs
@@ -1,3 +1,4 @@
+// tests1.rs
 // Tests are important to ensure that your code does what you think it should do.
 // Tests can be run on this file with the following command:
 // rustc --test tests1.rs
diff --git a/tests/tests2.rs b/tests/tests2.rs
index 0ae6ddb8..6775d610 100644
--- a/tests/tests2.rs
+++ b/tests/tests2.rs
@@ -1,3 +1,4 @@
+// tests2.rs
 // This test has a problem with it -- make the test compile! Make the test
 // pass! Make the test fail! Scroll down for hints :)
 
diff --git a/tests/tests3.rs b/tests/tests3.rs
index 1ee0f291..e041f385 100644
--- a/tests/tests3.rs
+++ b/tests/tests3.rs
@@ -1,3 +1,4 @@
+// tests3.rs
 // This test isn't testing our function -- make it do that in such a way that
 // the test passes. Then write a second test that tests that we get the result
 // we expect to get when we call `is_even(5)`. Scroll down for hints!
diff --git a/tests/tests4.rs b/tests/tests4.rs
index 278e29e8..23d444ad 100644
--- a/tests/tests4.rs
+++ b/tests/tests4.rs
@@ -1,3 +1,4 @@
+// tests4.rs
 // This test isn't testing our function -- make it do that in such a way that
 // the test passes. Then write a second test that tests that we get the result
 // we expect to get when we call `times_two` with a negative number.
diff --git a/threads/threads1.rs b/threads/threads1.rs
index af975521..d98db694 100644
--- a/threads/threads1.rs
+++ b/threads/threads1.rs
@@ -1,3 +1,4 @@
+// threads1.rs
 // Make this compile! Scroll down for hints :) The idea is the thread
 // spawned on line 17 is completing jobs while the main thread is
 // monitoring progress until 10 jobs are completed. If you see 6 lines
diff --git a/variables/variables1.rs b/variables/variables1.rs
index e0ad5de8..ffd661ce 100644
--- a/variables/variables1.rs
+++ b/variables/variables1.rs
@@ -1,3 +1,4 @@
+// variables1.rs
 // Make me compile! Scroll down for hints :)
 
 fn main() {
diff --git a/variables/variables2.rs b/variables/variables2.rs
index ca024387..348c2d80 100644
--- a/variables/variables2.rs
+++ b/variables/variables2.rs
@@ -1,3 +1,4 @@
+// variables2.rs
 // Make me compile! Scroll down for hints :)
 
 fn main() {
diff --git a/variables/variables3.rs b/variables/variables3.rs
index ec55a951..165a2779 100644
--- a/variables/variables3.rs
+++ b/variables/variables3.rs
@@ -1,3 +1,4 @@
+// variables3.rs
 // Make me compile! Scroll down for hints :)
 
 fn main() {
diff --git a/variables/variables4.rs b/variables/variables4.rs
index 3f7f937d..20ee64e6 100644
--- a/variables/variables4.rs
+++ b/variables/variables4.rs
@@ -1,3 +1,4 @@
+// variables4.rs
 // Make me compile! Scroll down for hints :)
 
 fn main() {