meta-[ outdents selected lines

src/app/composite-selection.coffee

@@ -91,6 +91,9 @@ class CompositeSeleciton
   insertText: (text) ->
     @mutateSelectedText (selection) -> selection.insertText(text)
 
+  outdentSelectedRows: ->
+    @mutateSelectedText (selection) -> selection.outdentSelectedRows()
+
   indentSelectedRows: ->
     @mutateSelectedText (selection) -> selection.indentSelectedRows()
 

src/app/editor.coffee

@@ -67,6 +67,7 @@ class Editor extends View
     @on 'newline', => @insertText("\n")
     @on 'tab', => @insertTab()
     @on 'indent-selected-rows', => @indentSelectedRows()
+    @on 'outdent-selected-rows', => @outdentSelectedRows()
     @on 'backspace', => @backspace()
     @on 'backspace-to-beginning-of-word', => @backspaceToBeginningOfWord()
     @on 'delete', => @delete()
@@ -425,8 +426,8 @@ class Editor extends View
     else
       @compositeSelection.insertText('\t')
 
-  indentSelectedRows: ->
-    @compositeSelection.indentSelectedRows()
+  indentSelectedRows: -> @compositeSelection.indentSelectedRows()
+  outdentSelectedRows: -> @compositeSelection.outdentSelectedRows()
 
   cutSelection: -> @compositeSelection.cut()
   copySelection: -> @compositeSelection.copy()

src/app/keymaps/editor.coffee

@@ -29,4 +29,5 @@ window.keymap.bindKeys '.editor',
   'alt-meta-right': 'split-right'
   'alt-meta-up': 'split-up'
   'alt-meta-down': 'split-down'
+  'meta-[': 'outdent-selected-rows'
   'meta-]': 'indent-selected-rows'

src/app/selection.coffee

@@ -110,6 +110,14 @@ class Selection extends View
     for row in [range.start.row..range.end.row]
       @editor.buffer.insert([row, 0], @editor.tabText) unless @editor.buffer.lineLengthForRow(row) == 0
 
+  outdentSelectedRows: ->
+    range = @getBufferRange()
+    buffer = @editor.buffer
+    leadingTabRegex = new RegExp("^#{@editor.tabText}")
+    for row in [range.start.row..range.end.row]
+      if leadingTabRegex.test buffer.lineForRow(row)
+        buffer.delete [[row, 0], [row, @editor.tabText.length]]
+
   autoIndentText: (text) ->
     if @editor.autoIndent
       mode = @editor.getCurrentMode()