How-to: Autoexec commands

To run a command as soon as the command prompt is opened, this can be useful for loading DOSKEY macros:

Add an entry in either:

This will also run if a CMD.exe session is initiated by drag and drop onto a batch file or by a FOR /F command which calls a sub-process.

The AutoRun entry can contain a string value (REG_SZ or REG_EXPAND_SZ) which will be executed. These AutoRun keys are rarely used and don’t exist by default.

Things not to do: if you set a Command Processor AutoRun which outputs any text, that is likely to mess up any scripts using the FOR /F command. If you set a Command Processor AutoRun to launch CMD.exe that will recursively launch new CMD sessions until the machine runs out of memory.

To run a command as soon as a user logs in:

To run a command as soon as any user logs in:

The \Microsoft\Windows NT\ keys exist largely for backwards compatibility, but are still supported.
There are also equivalent RunOnce keys which will execute just once and then be removed from the registry.

To run a command as soon as the machine powers up, (like AUTOEXEC.BAT in MS-DOS), use the Windows Task Scheduler - choosing the option:

Run a task:
When my computer starts (before a user logs on)

Autoexec.bat file

The autoexec.bat file was an MS-DOS feature. Under Windows there is a still a degree of backwards compatibility - if the file (C:\autoexec.bat) exists, any SET statements within it will be parsed at boot time.
Variables set in this way are not available to gui programs - they will be visible from the CMD prompt but don’t appear in the control panel. All other commands in autoexec.bat will be ignored. This behaviour is to allow old DOS applications to install correctly.

Scripts running at Windows startup

To see exactly what is running (or running slowly) at windows startup/login, set the following registry key:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system]
"verbosestatus"=dword:00000001

AutoRun

Autorun events are (mostly) restricted to drives of type DRIVE_CDROM. The default behaviour is to invoke AutoPlay. The NoAutoRun registry entry can be used to disable the AutoPlay and/or AutoRun feature on individual drives. This can be set in the registry under HKCU and/or HKLM. (If both are set then HKLM will take priority.)

The NoDriveTypeAutoRun registry entry disables or enables the AutoRun feature on all drives of the type specified. It can be set in the registry under HKCU and/or HKLM. (If both are set then HKLM will take priority.)

Values:
0xFF=Disable AutoRun on all types of drive
0x91=Disable AutoRun on network drives,
0x95=Disable AutoRun on removable + network drives.

The NoDriveAutoRun registry entry disables or enables the AutoRun feature on individual drives. It can be set in the registry under HKCU and/or HKLM. (If both are set then HKLM will take priority.)

In all cases the registry keys are set under:
\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

The registry key HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2 contains cached information about every removable device seen so far. This cache can bypass the registry settings above which can leave a machine vulnerable. See Q967715 for patches that address this issue. Alternatively the iniFileMapping method described below will disable AutoRun completely.

To effectively disable AutoRun in all versions of Microsoft Windows, import the following registry value (source: US-Cert Alert TA09-020A) this applies to any autorun.inf in any location and on any drive:

REGEDIT4
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\IniFileMapping\Autorun.inf]
@="@SYS:DoesNotExist"

“The real danger is not that machines will begin to think like men, but that men will begin to think like machines” ~ Sydney J. Harris

Related commands

DOSKEY - Edit command line, recall commands, and create macros.
SC - Service Control.
SET - Display, set, or remove Windows environment variables.
Microsoft - How to disable the Autorun functionality in Windows (registry: NoDriveAutoRun).
Q137890 - SRVANY - Create an NT Service from any executable. Not supported on current OS's use a Scheduled Task instead.


 
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