update to v2.0

https://github.com/ghacksuserjs/ghacks-user.js/issues/264#issuecomment-345462158

- It can now handle read-only files.
- it is somewhat more explicit regarding what it's doing in some circumstances. For example, it now informs the user when no changes are made.
- It now accepts two parameters: `-unattended` and `-log`
- Minor improvements here and there.

updater.bat

@@ -3,13 +3,23 @@ TITLE ghacks user.js updater
 
 REM ### ghacks-user.js updater for Windows
 REM ## author: @claustromaniac
-REM ## version: 1.0
+REM ## version: 2.0
 
 SETLOCAL EnableDelayedExpansion
+SET "_ua="
+SET "_log="
+:parse
+IF "%~1"=="" GOTO endparse
+IF "%~1"=="-unattended" SET "_ua=true"
+IF "%~1"=="-log" SET "_log=true"
+SHIFT
+GOTO parse
+:endparse
 SET "_name="
 SET "_date="
 SET "_version="
 SET /A "_line=0"
+ECHO.
 IF EXIST user.js (
 	FOR /F "delims=" %%i IN (user.js) DO (
 		IF !_line! EQU 1 SET "_name=%%i"
@@ -18,7 +28,7 @@ IF EXIST user.js (
 		SET /A "_line+=1"
 		IF !_line! GEQ 4 GOTO break
 	)
-	:break:
+	:break
 	IF !_line! GEQ 4 (
 		IF "ghacks"=="!_name:~8,6!" (
 			FOR /F "delims=:" %%G IN ("!_version!") DO SET "_version=%%G"
@@ -26,15 +36,30 @@ IF EXIST user.js (
 			SET "_date=!_date:~8!"
 			ECHO ghacks user.js !_version!, !_date!
 		) ELSE ( ECHO Current user.js version not recognised. )
-	)
-) ELSE ( ECHO user.js not found. )
+	) ELSE ( ECHO Current user.js version not recognised. )
+) ELSE ( ECHO user.js not detected in the current directory. )
 ECHO.
-ECHO This batch should be run from your Firefox profile directory. It will download the latest version of ghacks user.js from github and then append any of your own changes from user-overrides.js to it.
-ECHO.
-CHOICE /M "Continue"
-IF ERRORLEVEL 2 GOTO end
+IF NOT "%_ua%"=="true" (
+	ECHO This batch should be run from your Firefox profile directory. It will download the latest version of ghacks user.js from github and then append any of your own changes from user-overrides.js to it.
+	ECHO.
+	REM Visit the wiki for more detailed information.
+	REM ECHO.
+	CHOICE /M "Continue"
+	IF ERRORLEVEL 2 GOTO end
+)
 CLS
 ECHO.
+IF "%_log%"=="true" (
+	CALL :log >>user.js-update-log.txt
+	EXIT /B
+)
+:log
+IF "%_log%"=="true" (
+	ECHO ##################################################################
+	ECHO.
+	ECHO %date%, %time%
+	ECHO.
+)
 IF EXIST user.js (
 	IF EXIST user.js.bak REN user.js.bak user.js.old.bak
 	REN user.js user.js.bak
@@ -46,23 +71,39 @@ powershell -Command "(New-Object Net.WebClient).DownloadFile('https://github.com
 ECHO.
 IF EXIST user.js (
 	IF EXIST "user-overrides.js" (
-		COPY /b user.js+"user-overrides.js" "temp.js"
-		DEL user.js
-		REN temp.js user.js
+		ECHO Appending user-overrides.js...
+		ECHO.
+		COPY /B /V /Y user.js+"user-overrides.js" "tempuserjs"
+		DEL /F user.js
+		REN tempuserjs user.js
+		ECHO.
 	)
-	FC user.js.bak user.js >nul && DEL user.js.bak || IF EXIST user.js.old.bak DEL user.js.old.bak
-	IF EXIST user.js.old.bak REN user.js.old.bak user.js.bak
-	CLS
+	ECHO Handling backups...
+	SET "changed="
+	IF EXIST user.js.bak ( FC user.js.bak user.js >nul && SET "changed=false" || SET "changed=true" )
 	ECHO.
-	ECHO Successfully updated!
 	ECHO.
-	TIMEOUT 10
+	IF "!changed!"=="true" (
+		IF EXIST user.js.old.bak DEL /F user.js.old.bak
+		ECHO Update complete.
+	) ELSE (
+		IF "!changed!"=="false" (
+			DEL /F user.js.bak
+			IF EXIST user.js.old.bak REN user.js.old.bak user.js.bak
+			ECHO Update completed without changes.
+		) ELSE ECHO Update complete.
+	)
+	ECHO.
 ) ELSE (
 	IF EXIST user.js.bak REN user.js.bak user.js
 	IF EXIST user.js.old.bak REN user.js.old.bak user.js.bak
 	ECHO.
 	ECHO Update failed. Make sure PowerShell is allowed internet access.
 	ECHO.
-	PAUSE
+	ECHO No changes were made.
+	ECHO.
+)
+:end
+IF NOT "%_log%"=="true" (
+	IF NOT "%_ua%"=="true" PAUSE
 )
-:end: