diff --git a/lib/command.coffee b/lib/command.coffee
index 851f859..f7487ca 100644
--- a/lib/command.coffee
+++ b/lib/command.coffee
@@ -1,5 +1,6 @@
 ExViewModel = require './ex-view-model'
 Ex = require './ex'
+Find = require './find'
 
 class CommandError
   constructor: (@message) ->
@@ -9,9 +10,124 @@ class Command
   constructor: (@editor, @exState) ->
     @viewModel = new ExViewModel(@)
 
+  parseAddr: (str, curLine) ->
+    if str == '.'
+      addr = curLine
+    else if str == '$'
+      # Lines are 0-indexed in Atom, but 1-indexed in vim.
+      addr = @editor.getBuffer().lines.length - 1
+    else if str[0] in ["+", "-"]
+      addr = curLine + @parseOffset(str)
+    else if not isNaN(str)
+      addr = parseInt(str) - 1
+    else if str[0] == "'" # Parse Mark...
+      unless @vimState?
+        throw new CommandError("Couldn't get access to vim-mode.")
+      mark = @vimState.marks[str[1]]
+      unless mark?
+        throw new CommandError('Mark ' + str + ' not set.')
+      addr = mark.bufferMarker.range.end.row
+    else if str[0] == "/" # TODO: Parse forward search
+      addr = Find.findNext(@editor.buffer.lines, str[1...-1], curLine)
+      unless addr?
+        throw new CommandError('Pattern not found: ' + str[1...-1])
+    else if str[0] == "?" # TODO: Parse backwards search
+      addr = Find.findPrevious(@editor.buffer.lines, str[1...-1], curLine)
+      unless addr?
+        throw new CommandError('Pattern not found: ' + str[1...-1])
+
+    return addr
+
+  parseOffset: (str) ->
+    if str.length == 0
+      return 0
+    if str.length == 1
+      o = 1
+    else
+      o = parseInt(str[1..])
+    if str[0] == '+'
+      return o
+    else
+      return -o
+
   execute: (input) ->
-    return unless input.characters.length > 0
-    [command, args...] = input.characters.split(" ")
+    @vimState = @exState.globalExState.vim?.getEditorState(@editor)
+    # Command line parsing (mostly) following the rules at
+    # http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ex.html#tag_20_40_13_03
+    # Steps 1/2: Leading blanks and colons are ignored.
+    cl = input.characters
+    cl = cl.replace(/^(:|\s)*/, '')
+    return unless cl.length > 0
+    # Step 3: If the first character is a ", ignore the rest of the line
+    if cl[0] == '"'
+      return
+    # Step 4: Address parsing
+    lastLine = @editor.getBuffer().lines.length - 1
+    if cl[0] == '%'
+      range = [0, lastLine]
+      cl = cl[1..]
+    else
+      addrPattern = ///^
+        (?:                               # First address
+        (
+        \.|                               # Current line
+        \$|                               # Last line
+        \d+|                              # n-th line
+        '[\[\]<>'`"^.(){}a-zA-Z]|         # Marks
+        /.*?[^\\]/|                       # Regex
+        \?.*?[^\\]\?|                     # Backwards search
+        [+-]\d*                           # Current line +/- a number of lines
+        )((?:\s*[+-]\d*)*)                # Line offset
+        )?
+        (?:,                              # Second address
+        (                                 # Same as first address
+        \.|
+        \$|
+        \d+|
+        '[\[\]<>'`"^.(){}a-zA-Z]|
+        /.*?[^\\]/|
+        \?.*?[^\\]\?|
+        [+-]\d*
+        )((?:\s*[+-]\d*)*)
+        )?
+      ///
+
+      [match, addr1, off1, addr2, off2] = cl.match(addrPattern)
+
+      curLine = @editor.getCursorBufferPosition().row
+
+      if addr1?
+        address1 = @parseAddr(addr1, curLine)
+      else
+        # If no addr1 is given (,+3), assume it is '.'
+        address1 = curLine
+      if off1?
+        address1 += @parseOffset(off1)
+
+      if address1 < 0 or address1 > lastLine
+        throw new CommandError('Invalid range')
+
+      if addr2?
+        address2 = @parseAddr(addr2, curLine)
+      if off2?
+        address2 += @parseOffset(off2)
+
+      if address2 < 0 or address2 > lastLine
+        throw new CommandError('Invalid range')
+
+      if address2 < address1
+        throw new CommandError('Backwards range given')
+
+      range = [address1, if address2? then address2 else address1]
+      cl = cl[match?.length..]
+
+    # Step 5: Leading blanks are ignored
+    cl = cl.trimLeft()
+
+    # Vim behavior: If no command is specified, go to the specified length
+    if cl.length == 0
+      @editor.setCursorBufferPosition([range[1], 0])
+      return
 
     func = Ex.singleton()[command]
     if func?
diff --git a/lib/find.coffee b/lib/find.coffee
new file mode 100644
index 0000000..046ef4f
--- /dev/null
+++ b/lib/find.coffee
@@ -0,0 +1,26 @@
+module.exports = {
+  findLines: (lines, pattern) ->
+    # TODO: There's gotta be a better way to do this. Can we use vim-mode's
+    # search or find-and-replace maybe?
+    return (i for line, i in lines when line.match(pattern))
+
+  findNext: (lines, pattern, curLine) ->
+    lines = @findLines(lines, pattern)
+    if lines.length == 0
+      return null
+    more = (i for i in lines when i > curLine)
+    if more.length > 0
+      return more[0]
+    else
+      return lines[0]
+
+  findPrevious: (lines, pattern, curLine) ->
+    lines = @findLines(lines, pattern)
+    if lines.length == 0
+      return null
+    less = (i for i in lines when i < curLine)
+    if less.length > 0
+      return less[0]
+    else
+      return lines[lines.length - 1]
+}