Add Listing Files In IEx as an elixir til

README.md

@@ -10,7 +10,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 For a steady stream of TILs from a variety of rocketeers, checkout
 [til.hashrocket.com](https://til.hashrocket.com/).
 
-_521 TILs and counting..._
+_522 TILs and counting..._
 
 ---
 
@@ -112,6 +112,7 @@ _521 TILs and counting..._
 - [Expose Internal Representation](elixir/expose-internal-representation.md)
 - [Include Captures With String.split](elixir/include-captures-with-string-split.md)
 - [List Functions For A Module](elixir/list-functions-for-a-module.md)
+- [Listing Files In IEx](elixir/listing-files-in-iex.md)
 - [Pattern Matching In Anonymous Functions](elixir/pattern-matching-in-anonymous-functions.md)
 - [Quitting IEx](elixir/quitting-iex.md)
 - [Range Into List Using Comprehensions](elixir/range-into-list-using-comprehensions.md)

elixir/listing-files-in-iex.md

@@ -0,0 +1,20 @@
+# Listing Files In IEx
+
+When you start an IEx session, you do so in the context of some directory --
+the current working directory. This context can be important if you need to
+do something like import a file. In fact, you may want to know what files
+are available in the current working directory.
+
+You can list them all out within IEx using `ls/0`.
+
+```elixir
+iex(1)> ls()
+           .git     .gitignore      README.md         _build         assets         config
+           deps            lib        mix.exs       mix.lock           priv           test
+            tmp
+```
+
+You can also list the contents of some other specific directory by naming it
+when invoking `ls/1`.
+
+See `h()` within IEx for more details.