When working with batch scripts in Windows, retrieving the current process ID (PID) presents unique challenges compared to Unix-like systems. The Windows command shell lacks a direct built-in command like Unix's $$ variable. Many existing solutions rely on external utilities or make assumptions that might not hold in all environments.

Here are three reliable methods using only native Windows components:

@echo off
:: Method 1: Using WMIC
for /f "tokens=2 delims=," %%A in (
  'wmic process where "name='cmd.exe' and commandline like '%%%CD%%%'" get ProcessId^, CommandLine /format:csv'
) do set PID=%%A
echo Current PID: %PID%

For systems with PowerShell available (Windows 7 and later):

@echo off
:: Method 2: PowerShell one-liner
for /f %%A in ('powershell -command "$pid"') do set PID=%%A
echo Current PID: %PID%

A more robust version that handles multiple cmd.exe instances:

@echo off
:: Method 3: Precise WMIC filtering
setlocal enabledelayedexpansion
set UNIQUE=%RANDOM%-%TIME::=.%
title !UNIQUE!
for /f "tokens=2 delims=," %%A in (
  'wmic process where "name='cmd.exe' and caption='!UNIQUE!'" get ProcessId^, Caption /format:csv'
) do set PID=%%A
echo Current PID: %PID%
endlocal

For scripts needing repeated PID checks, the WMIC method adds ~200ms overhead per call, while PowerShell is faster (50-80ms). The title-based method is most reliable but modifies window properties.

Always include validation in production scripts:

@echo off
:: With error checking
for /f %%A in ('powershell -command "$pid" 2^>^&1') do (
  set PID=%%A
  if "!PID!" geq "0" (
    echo Valid PID: !PID!
  ) else (
    echo PID retrieval failed
  )
)

For Windows XP (without WMIC or PowerShell):

@echo off
:: Using tasklist filtering (less reliable)
for /f "tokens=2" %%A in (
  'tasklist /fi "windowtitle eq %CD%" /fo list ^| findstr "PID:"'
) do set PID=%%A

While working with Windows batch scripting, I recently faced a common but frustrating scenario - needing to programmatically obtain the current command prompt's process ID (PID) for script automation purposes. The immediate solution of using tasklist proves problematic because:

• Multiple cmd.exe instances create ambiguity
• The username column isn't always reliable in domain environments
• Window titles can be identical across sessions

The cleanest native solution combines cmd.exe with PowerShell's process capabilities:

:: In your batch file
for /f "tokens=2" %%a in ('powershell -command "$pid"') do set MY_PID=%%a
echo Current PID: %MY_PID%

This works because:

1. PowerShell's $pid always references its own process ID
2. The parent-child relationship preserves the PID when PowerShell is launched from cmd
3. No external dependencies required

For environments restricting PowerShell, WMIC provides another option:

@echo off
for /f "tokens=2 delims=," %%A in (
  'wmic process where "name='cmd.exe' and CommandLine like '%%%0%%%'" get ProcessId^, CommandLine /format:csv'
) do set PID=%%A
echo %PID%

Key points about this method:

• Filters cmd.exe processes containing the current script's name
• WMIC is deprecated in Windows 11, so consider forward compatibility
• The CSV format parsing handles spaces in paths better than other formats

When dealing with potential PID collisions, this enhanced version adds parent process verification:

@echo off
setlocal enabledelayedexpansion

:: Get parent PID
for /f "tokens=2" %%p in ('tasklist /fi "imagename eq cmd.exe" /fo csv /nh ^| findstr /i "%~nx0"') do (
  set "ppid=%%~p"
  for /f "tokens=2" %%a in (
    'wmic process where "ParentProcessId=!ppid!" get ProcessId /format:csv'
  ) do set child_pid=%%a
)

echo Current PID: %child_pid%

The fundamental advantage of these approaches is they either:

Each has trade-offs between compatibility (Windows version support) and reliability (edge case handling). For most modern environments, the PowerShell method offers the best combination of simplicity and robustness.