Controlling Windows Services from the Command Line

Windows Services are background processes that perform various system-level tasks. Often, you need to start, stop, or query these services from a command-line environment, such as within a batch file or script. This tutorial will guide you through effectively managing Windows Services from the command line, including error handling to ensure your scripts are robust.

Understanding the Tools

Windows provides several command-line tools for service management:

net start / net stop: These are the simplest commands for starting and stopping services. They provide basic functionality and clear output indicating success or failure.
sc (Service Control): A more powerful and flexible command-line tool for managing services. It offers a wider range of options, including querying service status, configuring startup types, and more.
tasklist & taskkill: While primarily used for processes, these can indirectly affect services if a service runs as a process.

Basic Service Control with `net`

The net commands are straightforward to use.

Starting a Service:

net start "Service Name"

Replace "Service Name" with the actual name of the service you wish to start. The service name is not necessarily the display name.

Stopping a Service:

net stop "Service Name"

Similar to net start, use the correct service name.

Checking for Success/Failure

The net commands will output a message indicating whether the operation was successful. However, for scripting, it’s crucial to check the ERRORLEVEL environment variable. A value of 0 indicates success; any other value indicates an error.

@echo off
net start "MyService"
if %errorlevel% == 0 (
  echo Service started successfully.
) else (
  echo Failed to start service. Error code: %errorlevel%
)

Advanced Service Control with `sc`

The sc command provides more control and options.

Querying Service Status:

sc query "Service Name"

This will display detailed information about the service, including its state, PID, and other properties.

Configuring Startup Type:

You can change how a service starts (e.g., automatically, manually, disabled) using sc config.

Automatic:
```
sc config "Service Name" start= auto
```
Manual:
```
sc config "Service Name" start= demand
```

Disabled:

sc config "Service Name" start= disabled

Starting/Stopping with sc:

sc start "Service Name"
sc stop "Service Name"

Robust Error Handling in Batch Scripts

For reliable scripts, proper error handling is essential. Here are some techniques:

Checking ERRORLEVEL:

As demonstrated earlier, always check the ERRORLEVEL after executing a command.

Using || for Conditional Execution:

The || operator allows you to execute a command only if the previous command failed (i.e., ERRORLEVEL is not 0).

net start "MyService" || goto Error
:End
exit /b 0
:Error
echo Failed to start service.
exit /b 1

This code attempts to start the service. If it fails, the script jumps to the :Error label, displays an error message, and exits with a non-zero error code.

Complete Example Script

Here’s a more comprehensive example combining service control and error handling:

@echo off
setlocal

set "ServiceName=MyService"

echo Attempting to stop %ServiceName%...
net stop "%ServiceName%"
if %errorlevel% neq 0 (
    echo Failed to stop %ServiceName%. Error code: %errorlevel%
    exit /b 1
)

echo Attempting to start %ServiceName%...
net start "%ServiceName%"
if %errorlevel% neq 0 (
    echo Failed to start %ServiceName%. Error code: %errorlevel%
    exit /b 1
)

echo Service %ServiceName% stopped and started successfully.
exit /b 0

endlocal

This script attempts to stop and then start a specified service, providing error messages and exit codes if any step fails. The endlocal command restores the environment variables to their original state.

Important Considerations

Service Names vs. Display Names: Ensure you use the correct service name when using command-line tools. The display name is what you see in the Services manager, but the service name is used by the command line.
Permissions: You may need administrator privileges to start, stop, or configure certain services. Run your batch file with elevated permissions if necessary.
Dependencies: Be aware of service dependencies. Stopping a service that other services rely on may cause issues.