diff --git a/moonscript/cmd/watcher.lua b/moonscript/cmd/watcher.lua
new file mode 100644
index 0000000..52be1d5
--- /dev/null
+++ b/moonscript/cmd/watcher.lua
@@ -0,0 +1,149 @@
+local remove_dupes
+remove_dupes = function(list, key_fn)
+  local seen = { }
+  return (function()
+    local _accum_0 = { }
+    local _len_0 = 1
+    for _index_0 = 1, #list do
+      local _continue_0 = false
+      repeat
+        local item = list[_index_0]
+        local key
+        if key_fn then
+          key = key_fn(item)
+        else
+          key = item
+        end
+        if seen[key] then
+          _continue_0 = true
+          break
+        end
+        seen[key] = true
+        local _value_0 = item
+        _accum_0[_len_0] = _value_0
+        _len_0 = _len_0 + 1
+        _continue_0 = true
+      until true
+      if not _continue_0 then
+        break
+      end
+    end
+    return _accum_0
+  end)()
+end
+local Watcher
+do
+  local _class_0
+  local _base_0 = { }
+  _base_0.__index = _base_0
+  _class_0 = setmetatable({
+    __init = function(self, file_list)
+      self.file_list = file_list
+    end,
+    __base = _base_0,
+    __name = "Watcher"
+  }, {
+    __index = _base_0,
+    __call = function(cls, ...)
+      local _self_0 = setmetatable({}, _base_0)
+      cls.__init(_self_0, ...)
+      return _self_0
+    end
+  })
+  _base_0.__class = _class_0
+  Watcher = _class_0
+end
+local InotifyWacher
+do
+  local _class_0
+  local _parent_0 = Watcher
+  local _base_0 = {
+    get_dirs = function(self)
+      local parse_dir
+      parse_dir = require("moonscript.cmd.moonc").parse_dir
+      local dirs
+      do
+        local _accum_0 = { }
+        local _len_0 = 1
+        local _list_0 = self.file_list
+        for _index_0 = 1, #_list_0 do
+          local _des_0 = _list_0[_index_0]
+          local file_path
+          file_path = _des_0[1]
+          local dir = parse_dir(file_path)
+          if dir == "" then
+            dir = "./"
+          end
+          local _value_0 = dir
+          _accum_0[_len_0] = _value_0
+          _len_0 = _len_0 + 1
+        end
+        dirs = _accum_0
+      end
+      return remove_dupes(dirs)
+    end
+  }
+  _base_0.__index = _base_0
+  setmetatable(_base_0, _parent_0.__base)
+  _class_0 = setmetatable({
+    __init = function(self, ...)
+      return _class_0.__parent.__init(self, ...)
+    end,
+    __base = _base_0,
+    __name = "InotifyWacher",
+    __parent = _parent_0
+  }, {
+    __index = function(cls, name)
+      local val = rawget(_base_0, name)
+      if val == nil then
+        local parent = rawget(cls, "__parent")
+        if parent then
+          return parent[name]
+        end
+      else
+        return val
+      end
+    end,
+    __call = function(cls, ...)
+      local _self_0 = setmetatable({}, _base_0)
+      cls.__init(_self_0, ...)
+      return _self_0
+    end
+  })
+  _base_0.__class = _class_0
+  local self = _class_0
+  self.available = function(self)
+    return pcall(function()
+      return require("inotify")
+    end)
+  end
+  if _parent_0.__inherited then
+    _parent_0.__inherited(_parent_0, _class_0)
+  end
+  InotifyWacher = _class_0
+end
+local SleepWatcher
+do
+  local _class_0
+  local _base_0 = { }
+  _base_0.__index = _base_0
+  _class_0 = setmetatable({
+    __init = function() end,
+    __base = _base_0,
+    __name = "SleepWatcher"
+  }, {
+    __index = _base_0,
+    __call = function(cls, ...)
+      local _self_0 = setmetatable({}, _base_0)
+      cls.__init(_self_0, ...)
+      return _self_0
+    end
+  })
+  _base_0.__class = _class_0
+  SleepWatcher = _class_0
+end
+return {
+  Watcher = Watcher,
+  SleepWatcher = SleepWatcher,
+  InotifyWacher = InotifyWacher
+}
diff --git a/moonscript/cmd/watcher.moon b/moonscript/cmd/watcher.moon
new file mode 100644
index 0000000..afb5dd7
--- /dev/null
+++ b/moonscript/cmd/watcher.moon
@@ -0,0 +1,29 @@
+remove_dupes = (list, key_fn) ->
+  seen = {}
+  return for item in *list
+    key = if key_fn then key_fn item else item
+    continue if seen[key]
+    seen[key] = true
+    item
+
+-- files is a list of tuples, {source, target}
+class Watcher
+  new: (@file_list) =>
+
+
+class InotifyWacher extends Watcher
+  @available: =>
+    pcall -> require "inotify"
+
+  get_dirs: =>
+    import parse_dir from require "moonscript.cmd.moonc"
+    dirs = for {file_path} in *@file_list
+      dir = parse_dir file_path
+      dir = "./" if dir == ""
+      dir
+
+    remove_dupes dirs
+
+class SleepWatcher
+
+{:Watcher, :SleepWatcher, :InotifyWacher}
diff --git a/spec/cmd_spec.moon b/spec/cmd_spec.moon
index 5e7b0dc..2ab5199 100644
--- a/spec/cmd_spec.moon
+++ b/spec/cmd_spec.moon
@@ -9,7 +9,7 @@ describe "moonc", ->
   dev_loaded = with_dev ->
     moonc = require "moonscript.cmd.moonc"
 
-  same = (fn, a, b)->
+  same = (fn, a, b) ->
     assert.same b, fn a
 
   it "should normalize dir", ->
@@ -18,7 +18,6 @@ describe "moonc", ->
     same moonc.normalize_dir, "", "/" -- wrong
     same moonc.normalize_dir, "hello", "hello/"
 
-
   it "should parse dir", ->
     same moonc.parse_dir, "/hello/world/file", "/hello/world/"
     same moonc.parse_dir, "/hello/world/", "/hello/world/"
@@ -63,6 +62,21 @@ describe "moonc", ->
       moonc.compile_file_text "print'hello'", fname: "test.moon"
     }
 
+  describe "watcher", ->
+    describe "inotify watcher", ->
+      it "gets dirs", ->
+        import InotifyWacher from require "moonscript.cmd.watcher"
+        watcher = InotifyWacher {
+          {"hello.moon", "hello.lua"}
+          {"cool/no.moon", "cool/no.lua"}
+        }
+
+        assert.same {
+          "./"
+          "cool/"
+        }, watcher\get_dirs!
+
+
   describe "stubbed lfs", ->
     local dirs