Add Buffer.save

src/atom/buffer.coffee

@@ -7,9 +7,18 @@ class Buffer
   url: null
 
   constructor: (@url) ->
-    text = if @url then fs.read(@url) else ""
+    text = if @url and fs.exists(@url)
+      fs.read(@url)
+    else
+      ""
     @aceDocument = new Document text
 
   getText: ->
     @aceDocument.getValue()
 
+  setText: (text) ->
+    @aceDocument.setValue text
+
+  save: ->
+    if not @url then throw new Error("Tried to save buffer with no url")
+    fs.write @url, @getText()

src/atom/editor.coffee

@@ -25,4 +25,3 @@ class Editor
   getAceSession: ->
     @aceEditor.getSession()
 
-

src/stdlib/fs.coffee

@@ -67,6 +67,12 @@ module.exports =
   listDirectoryTree: (path) ->
     @list path, true
 
+  # Remove a file at the given path. Throws an error if path is not a
+  # file or a symbolic link to a file.
+  remove: (path) ->
+    fm = OSX.NSFileManager.defaultManager
+    paths = fm.removeItemAtPath_error path, null
+
   # Open, read, and close a file, returning the file's contents.
   read: (path) ->
     path = @absolute path