Skypher » batch scripts

Delayed environment variable expansion and command extensions in CMD.EXE

SkyLined — Thu, 17 Sep 2009 16:01:16 +0000

If you want to use delayed environment variable expansion and command extensions in a batch script, here’s a batch script that functions as a useful cheat sheet for setting, detecting and using them:

@ECHO OFF IF “%1″ == “TEST_EOF” ( GOTO :EOF ) ELSE IF “%1″ == “TEST_EXPANSION” ( SET extensions=enabled IF “!extensions!”==”enabled” ( ECHO Delayed environment variable expansion = ON ) ELSE ( ECHO Delayed environment variable expansion = OFF ) ) ELSE IF “%1″ == “TEST_EXTENSIONS” ( :: CALL :label is not available if test extensions are disabled. CALL %0 TEST_EOF 2>nul IF NOT ERRORLEVEL 1 ( ECHO Command extensions = ON ) ELSE ( ECHO Command extensions = OFF ) ) ELSE ( ECHO == Default == CALL %0 TEST_EXPANSION CALL %0 TEST_EXTENSIONS ECHO. ECHO == Enabled == SETLOCAL ENABLEDELAYEDEXPANSION ENABLEEXTENSIONS CALL %0 TEST_EXPANSION CALL %0 TEST_EXTENSIONS ENDLOCAL ECHO. ECHO == Disabled == SETLOCAL DISABLEDELAYEDEXPANSION DISABLEEXTENSIONS CALL %0 TEST_EXPANSION CALL %0 TEST_EXTENSIONS ENDLOCAL )
(download the script here).

Here’s the output of a run on my machine:

== Default == Delayed environment variable expansion = OFF Command extensions = ON == Enabled == Delayed environment variable expansion = ON Command extensions = ON == Disabled == Delayed environment variable expansion = OFF Command extensions = OFF

GNU which for Windows: which.cmd

SkyLined — Mon, 07 Sep 2009 09:15:15 +0000

I’ve implemented GNU which as a batch script for Windows. GNU which is a utility that is used to find which executable (or alias or shell function) is executed when entered on the shell prompt. Which.cmd does a similar job for windows: it finds which application or script is executed when you execute a command. It works by going through the list of executable extension in the “%PATHEXT%” environment variable and then searches through the “%PATH%” environment variable for a file with the name you provide on the command line for each extension. When it finds a match, it is displayed, when it finds nothing, it reports an error.

Example:
C:\>which explorer C:\Windows\explorer.exe C:\>which cmd.exe C:\Windows\System32\cmd.exe C:\>which nc C:\Tools\nc.exe C:\>which blablablabla “blablablabla” not found

You can download the batch script here.

BATCH & Python Chimera code

SkyLined — Thu, 19 Feb 2009 15:12:09 +0000

I’ve create an example of how to create a file that can be run both as a valid cmd.exe batch script as well as a valid Python script. This would be useful if python.exe is available on a system but not set up to handle .py files: a .cmd file can be used to automatically find the python exe and run the script.

The example can be found here.

Fuzzing Opera browser: how to get rid of the “start-up dialog” after a crash

SkyLined — Thu, 23 Oct 2008 15:50:19 +0000

If you want to automate running Opera to run fuzzers, you’ll find that once you’ve crashed Opera, it does not start as normal the next time you run it. Opera had provided a “start-up dialog” for your convenience that shows up after you’ve crashed it. Also, Opera has a session restore feature that can cause problems when you start Opera using the command-line to open a URL; it will open the pages from the previous session as well. Unfortunately, I was unable to find configuration settings to disabled either one of these features.

To get around these problems I’ve created a program that will modify the “Opera.ini” file as well as delete the session folder. If you run this program, it will remove all traces of a crash that cause Opera to open the start-up dialog and restore the previous session. After running it, you can start Opera as usual.

On the off chance that you’ve encountered this problem, I’ve made the program available here. The program is called “dirtyOperaHack.cmd”. It is a chimera file; part JavaScript, part batch-file. I’ve also included the individual source files from which it was created for your convenience. You can run “make.cmd” to create ”dirtyOperaHack.cmd” from the individual source files.

UPDATE
Opera 10 seems to have changed the paths for some of these settings. I have an updated version of my “Dirty Opera Hack” script available here.