diff --git a/src/moe.nim b/src/moe.nim
index 7ff1724a7..b0f681327 100644
--- a/src/moe.nim
+++ b/src/moe.nim
@@ -17,6 +17,18 @@ proc loadPersistData(status: var EditorStatus) =
     currentMainWindowNode.restoreCursorPostion(currentBufStatus,
                                                status.lastPosition)
 
+proc addBufferStatus(status: var EditorStatus,
+                     parsedList: CmdParsedList) =
+
+  if parsedList.path.len > 0:
+    for path in parsedList.path:
+      if dirExists(path):
+        status.addNewBuffer(path, Mode.filer)
+      else:
+        status.addNewBuffer(path)
+  else:
+    status.addNewBuffer
+
 proc initEditor(): EditorStatus =
   let parsedList = parseCommandLineOption(commandLineParams())
 
@@ -33,14 +45,10 @@ proc initEditor(): EditorStatus =
     exitUi()
     quit())
 
-  if parsedList.len > 0:
-    for p in parsedList:
-      if dirExists(p.filename):
-        result.addNewBuffer(p.filename, Mode.filer)
-      else:
-        result.addNewBuffer(p.filename)
-  else:
-    result.addNewBuffer
+  if parsedList.isReadonly:
+    result.isReadonly = true
+
+  result.addBufferStatus(parsedList)
 
   result.loadPersistData
 
diff --git a/src/moepkg/bufferstatus.nim b/src/moepkg/bufferstatus.nim
index 0166fc04c..e9f9474c5 100644
--- a/src/moepkg/bufferstatus.nim
+++ b/src/moepkg/bufferstatus.nim
@@ -40,6 +40,7 @@ type BufferStatus* = object
   mode* : Mode
   prevMode* : Mode
   lastSaveTime*: DateTime
+  isReadonly*: bool
 
 proc initBufferStatus*(path: seq[Rune], mode: Mode): BufferStatus {.inline.} =
   BufferStatus(isUpdate: true, path: path, mode: mode, lastSaveTime: now())
diff --git a/src/moepkg/cmdlineoption.nim b/src/moepkg/cmdlineoption.nim
index a48e97458..1beeb1e98 100644
--- a/src/moepkg/cmdlineoption.nim
+++ b/src/moepkg/cmdlineoption.nim
@@ -1,6 +1,8 @@
 import parseopt, pegs, os, strformat
 
-type CmdParsedList* = seq[tuple[filename: string]]
+type CmdParsedList* = object
+  path*: seq[string]
+  isReadonly*: bool
 
 proc staticReadVersionFromNimble: string {.compileTime.} =
   let peg = """@ "version" \s* "=" \s* \" {[0-9.]+} \" @ $""".peg
@@ -34,6 +36,7 @@ Usage:
   moe [file]       Edit file
 
 Arguments:
+  -R               Readonly mode
   -h, --help       Print this help
   -v, --version    Print version
 """
@@ -59,11 +62,12 @@ proc parseCommandLineOption*(line: seq[string]): CmdParsedList =
   for kind, key, val in parsedLine.getopt():
     case kind:
       of cmdArgument:
-        result.add((filename: key))
+        result.path.add(key)
       of cmdShortOption:
         case key:
           of "v": writeVersion()
           of "h": writeHelp()
+          of "R": result.isReadonly = true
           else: writeCmdLineError(kind, key)
       of cmdLongOption:
         case key:
diff --git a/src/moepkg/editorstatus.nim b/src/moepkg/editorstatus.nim
index 630f568c2..4078fbe56 100644
--- a/src/moepkg/editorstatus.nim
+++ b/src/moepkg/editorstatus.nim
@@ -31,6 +31,7 @@ type EditorStatus* = object
   autoBackupStatus*: AutoBackupStatus
   isSearchHighlight*: bool
   lastPosition*: seq[LastPosition]
+  isReadonly*: bool
 
 proc initEditorStatus*(): EditorStatus =
   result.currentDir = getCurrentDir().toRunes
@@ -723,6 +724,8 @@ proc addNewBuffer*(status: var EditorStatus, filename: string, mode: Mode) =
 
   let index = status.bufStatus.high
 
+  status.bufStatus[index].isReadonly = status.isReadonly
+
   if mode != Mode.filer:
     if not fileExists(filename):
       status.bufStatus[index].buffer = newFile()
diff --git a/src/moepkg/messages.nim b/src/moepkg/messages.nim
index ea6af8e1c..2ae5664b6 100644
--- a/src/moepkg/messages.nim
+++ b/src/moepkg/messages.nim
@@ -4,10 +4,12 @@ import color, unicodeext, settings, commandline, independentutils
 proc writeMessageOnCommandWindow*(commandLine: var CommandLine,
                                   message: string,
                                   color: EditorColorPair) {.inline.} =
+
   commandLine.updateCommandBuffer(ru message, color)
 
 proc writeMessageOnCommandWindow*(commandLine: var CommandLine,
                                   message: string) {.inline.} =
+
   commandLine.writeMessageOnCommandWindow(message, EditorColorPair.commandBar)
 
 proc writeNoWriteError*(commandLine: var CommandLine, messageLog: var seq[seq[Rune]]) =
@@ -296,3 +298,7 @@ proc writeCurrentCharInfo*(commandLine: var CommandLine, r: Rune) {.inline.} =
     eOct = int64(e[0]).toOct(5)
     mess = fmt "<{$r}>  {e[0]}  Hex {normalizeHex($eHex)}  Oct {$eOct}"
   commandLine.writeMessageOnCommandWindow(mess)
+
+proc writeReadonlyModeWarning*(commandLine: var CommandLine) {.inline.} =
+  const mess = "Warning: Readonly mode"
+  commandLine.writeMessageOnCommandWindow(mess, EditorColorPair.errorMessage)
diff --git a/src/moepkg/normalmode.nim b/src/moepkg/normalmode.nim
index 2d9aef937..b27c46c78 100644
--- a/src/moepkg/normalmode.nim
+++ b/src/moepkg/normalmode.nim
@@ -155,6 +155,10 @@ proc yankWord(status: var EditorStatus, registerName: string) =
                             status.settings)
 
 proc deleteWord(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const registerName = ""
   currentBufStatus.deleteWord(
     currentMainWindowNode,
@@ -173,6 +177,10 @@ proc deleteWord(status: var EditorStatus, registerName: string) =
 
 # ci command
 proc changeInnerCommand(status: var EditorStatus, key: Rune) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   let
     currentLine = currentMainWindowNode.currentLine
     oldLine = currentBufStatus.buffer[currentLine]
@@ -202,6 +210,10 @@ proc changeInnerCommand(status: var EditorStatus,
                         key: Rune,
                         registerName: string) =
 
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   let
     currentLine = currentMainWindowNode.currentLine
     oldLine = currentBufStatus.buffer[currentLine]
@@ -229,6 +241,10 @@ proc changeInnerCommand(status: var EditorStatus,
 
 # di command
 proc deleteInnerCommand(status: var EditorStatus, key: Rune, registerName: string) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   # Delete inside paren and enter insert mode
   if isParen(key):
     if registerName.len > 0:
@@ -256,6 +272,10 @@ proc deleteInnerCommand(status: var EditorStatus, key: Rune, registerName: strin
 
 # di command
 proc deleteInnerCommand(status: var EditorStatus, key: Rune) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const registerName = ""
   status.deleteInnerCommand(key, registerName)
 
@@ -368,6 +388,10 @@ proc yankToNextBlankLine(status: var EditorStatus) =
 
 # dd command
 proc deleteLines(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const registerName = ""
   let
     startLine = currentMainWindowNode.currentLine
@@ -382,6 +406,10 @@ proc deleteLines(status: var EditorStatus) =
                                status.settings)
 
 proc deleteLines(status: var EditorStatus, registerName: string) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   let
     startLine = currentMainWindowNode.currentLine
     count = min(
@@ -436,6 +464,10 @@ proc yankCharacters(status: var Editorstatus, registerName: string) =
     isDelete)
 
 proc deleteCharacters(status: var EditorStatus, registerName: string) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   currentBufStatus.deleteCharacters(
     status.registers,
     registerName,
@@ -445,6 +477,10 @@ proc deleteCharacters(status: var EditorStatus, registerName: string) =
     status.settings)
 
 proc deleteCharacters(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const registerName = ""
   currentBufStatus.deleteCharacters(
     status.registers,
@@ -458,6 +494,10 @@ proc deleteCharacters(status: var EditorStatus) =
 proc deleteCharactersUntilEndOfLine(status: var EditorStatus,
                                     registerName: string) =
 
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   let lineWidth = currentBufStatus.buffer[currentMainWindowNode.currentLine].len
   currentBufStatus.cmdLoop = lineWidth - currentMainWindowNode.currentColumn
 
@@ -469,6 +509,10 @@ proc deleteCharactersUntilEndOfLine(status: var EditorStatus,
 
 # d$ command
 proc deleteCharactersUntilEndOfLine(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   let lineWidth = currentBufStatus.buffer[currentMainWindowNode.currentLine].len
   currentBufStatus.cmdLoop = lineWidth - currentMainWindowNode.currentColumn
 
@@ -483,6 +527,10 @@ proc deleteCharactersUntilEndOfLine(status: var EditorStatus) =
 proc deleteCharacterBeginningOfLine(status: var EditorStatus,
                                     registerName: string) =
 
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   currentBufStatus.deleteCharacterBeginningOfLine(
     status.registers,
     currentMainWindowNode,
@@ -491,6 +539,10 @@ proc deleteCharacterBeginningOfLine(status: var EditorStatus,
 
 # d0 command
 proc deleteCharacterBeginningOfLine(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const registerName = ""
   status.deleteCharacterBeginningOfLine(registerName)
 
@@ -499,6 +551,10 @@ proc deleteCharacterBeginningOfLine(status: var EditorStatus) =
 proc deleteFromCurrentLineToLastLine(status: var EditorStatus,
                                      registerName: string) =
 
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   let
     startLine = currentMainWindowNode.currentLine
     count = currentBufStatus.buffer.len - currentMainWindowNode.currentLine
@@ -514,6 +570,10 @@ proc deleteFromCurrentLineToLastLine(status: var EditorStatus,
 proc deleteLineFromFirstLineToCurrentLine(status: var EditorStatus,
                                           registerName: string) =
 
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const startLine = 0
   let count = currentMainWindowNode.currentLine
   currentBufStatus.deleteLines(status.registers,
@@ -529,6 +589,10 @@ proc deleteLineFromFirstLineToCurrentLine(status: var EditorStatus,
 proc deleteTillPreviousBlankLine(status: var EditorStatus,
                                  registerName: string) =
 
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   currentBufStatus.deleteTillPreviousBlankLine(
     status.registers,
     currentMainWindowNode,
@@ -536,6 +600,10 @@ proc deleteTillPreviousBlankLine(status: var EditorStatus,
     status.settings)
 
 proc deleteTillPreviousBlankLine(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const registerName = ""
   status.deleteTillPreviousBlankLine(registerName)
 
@@ -543,6 +611,10 @@ proc deleteTillPreviousBlankLine(status: var EditorStatus) =
 proc deleteTillNextBlankLine(status: var EditorStatus,
                              registerName: string) =
 
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   currentBufStatus.deleteTillNextBlankLine(
     status.registers,
     currentMainWindowNode,
@@ -551,6 +623,10 @@ proc deleteTillNextBlankLine(status: var EditorStatus,
 
 # X and dh command
 proc cutCharacterBeforeCursor(status: var EditorStatus, registerName: string) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   if currentMainWindowNode.currentColumn > 0:
     let
       currentColumn = currentMainWindowNode.currentColumn
@@ -564,23 +640,43 @@ proc cutCharacterBeforeCursor(status: var EditorStatus, registerName: string) =
 
 # X and dh command
 proc cutCharacterBeforeCursor(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const registerName = ""
   status.cutCharacterBeforeCursor(registerName)
 
 proc deleteTillNextBlankLine(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const registerName = ""
   status.deleteTillNextBlankLine(registerName)
 
 proc deleteLineFromFirstLineToCurrentLine(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const registerName = ""
   status.deleteLineFromFirstLineToCurrentLine(registerName)
 
 proc deleteFromCurrentLineToLastLine(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const registerName = ""
   status.deleteFromCurrentLineToLastLine(registerName)
 
 # s and cl commands
 proc deleteCharacterAndEnterInsertMode(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   if currentBufStatus.buffer[currentMainWindowNode.currentLine].len > 0:
     let
       lineWidth = currentBufStatus.buffer[currentMainWindowNode.currentLine].len
@@ -596,6 +692,10 @@ proc deleteCharacterAndEnterInsertMode(status: var EditorStatus) =
 proc deleteCharacterAndEnterInsertMode(status: var EditorStatus,
                                        registerName: string) =
 
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   if currentBufStatus.buffer[currentMainWindowNode.currentLine].len > 0:
     let
       lineWidth = currentBufStatus.buffer[currentMainWindowNode.currentLine].len
@@ -609,6 +709,10 @@ proc deleteCharacterAndEnterInsertMode(status: var EditorStatus,
 
 # cc/S command
 proc deleteCharactersAfterBlankInLine(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   const registerName = ""
   currentBufStatus.deleteCharactersAfterBlankInLine(
     status.registers,
@@ -617,6 +721,10 @@ proc deleteCharactersAfterBlankInLine(status: var EditorStatus) =
     status.settings)
 
 proc enterInsertModeAfterCursor(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   let lineWidth = currentBufStatus.buffer[currentMainWindowNode.currentLine].len
   if lineWidth == 0: discard
   elif lineWidth == currentMainWindowNode.currentColumn: discard
@@ -624,11 +732,19 @@ proc enterInsertModeAfterCursor(status: var EditorStatus) =
   status.changeMode(Mode.insert)
 
 proc toggleCharacterAndMoveRight(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   currentBufStatus.toggleCharacters(
     currentMainWindowNode,
     currentBufStatus.cmdLoop)
 
 proc replaceCurrentCharacter(status: var EditorStatus, newCharacter: Rune) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   currentBufStatus.replaceCharacters(
     currentMainWindowNode,
     status.settings.autoIndent,
@@ -638,12 +754,20 @@ proc replaceCurrentCharacter(status: var EditorStatus, newCharacter: Rune) =
     newCharacter)
 
 proc openBlankLineBelowAndEnterInsertMode(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   currentBufStatus.openBlankLineBelow(currentMainWindowNode,
                                       status.settings.autoIndent,
                                       status.settings.tabStop)
   status.changeMode(Mode.insert)
 
 proc openBlankLineAboveAndEnterInsertMode(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   currentBufStatus.openBlankLineAbove(currentMainWindowNode,
                                       status.settings.autoIndent,
                                       status.settings.tabStop)
@@ -658,6 +782,23 @@ proc openBlankLineAboveAndEnterInsertMode(status: var EditorStatus) =
 
   status.changeMode(Mode.insert)
 
+proc moveToFirstNonBlankOfLineAndEnterInsertMode(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
+  currentBufStatus.moveToFirstNonBlankOfLine(currentMainWindowNode)
+  status.changeMode(Mode.insert)
+
+proc moveToEndOfLineAndEnterInsertMode(status: var EditorStatus) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
+  let lineLen = currentBufStatus.buffer[currentMainWindowNode.currentLine].len
+  currentMainWindowNode.currentColumn = lineLen
+  status.changeMode(Mode.insert)
+
 proc closeCurrentWindow(status: var EditorStatus, height, width: int) =
   if status.mainWindow.numOfMainWindow == 1: return
 
@@ -706,6 +847,10 @@ proc addRegister(status: var EditorStatus, command, registerName: string) =
     discard
 
 proc pasteFromRegister(status: var EditorStatus, command, name: string) =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+    return
+
   if name.len == 0: return
 
   case command:
@@ -793,6 +938,30 @@ proc isChangeModeKey(key: Rune): bool =
           key == ord('a') or
           key == ord('A')
 
+proc changeModeToInsertMode(status: var EditorStatus) {.inline.} =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+  else:
+    status.changeMode(Mode.insert)
+
+proc changeModeToReplaceMode(status: var EditorStatus) {.inline.} =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+  else:
+    status.changeMode(Mode.replace)
+
+proc changeModeToVisualMode(status: var EditorStatus) {.inline.} =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+  else:
+    status.changeMode(Mode.visual)
+
+proc changeModeToVisualBlockMode(status: var EditorStatus) {.inline.} =
+  if currentBufStatus.isReadonly:
+    status.commandLine.writeReadonlyModeWarning
+  else:
+    status.changeMode(Mode.visualBlock)
+
 proc normalCommand(status: var EditorStatus,
                    commands: seq[Rune],
                    height, width: int) =
@@ -812,7 +981,7 @@ proc normalCommand(status: var EditorStatus,
   elif isControlJ(key):
     status.movePrevWindow
   elif isControlV(key):
-    status.changeMode(Mode.visualBlock)
+    status.changeModeToVisualBlockMode
   elif key == ord('h') or isLeftKey(key) or isBackspaceKey(key):
     for i in 0 ..< cmdLoop: currentMainWindowNode.keyLeft
   elif key == ord('l') or isRightKey(key):
@@ -982,20 +1151,17 @@ proc normalCommand(status: var EditorStatus,
       currentMainWindowNode,
       secondKey)
   elif key == ord('R'):
-    status.changeMode(Mode.replace)
+    status.changeModeToReplaceMode
   elif key == ord('i'):
-    status.changeMode(Mode.insert)
+    status.changeModeToInsertMode
   elif key == ord('I'):
-    currentBufStatus.moveToFirstNonBlankOfLine(currentMainWindowNode)
-    status.changeMode(Mode.insert)
+    status.moveToFirstNonBlankOfLineAndEnterInsertMode
   elif key == ord('v'):
-    status.changeMode(Mode.visual)
+    status.changeModeToVisualMode
   elif key == ord('a'):
     status.enterInsertModeAfterCursor
   elif key == ord('A'):
-    let lineLen = currentBufStatus.buffer[currentMainWindowNode.currentLine].len
-    currentMainWindowNode.currentColumn = lineLen
-    status.changeMode(Mode.insert)
+    status.moveToEndOfLineAndEnterInsertMode
   elif key == ord('u'):
     status.bufStatus[currentBufferIndex].undo(currentMainWindowNode)
   elif isControlR(key):