How to Compare Files in Two Folders Windows 10

Comparing files in two folders on Windows 10 can be crucial for various tasks, from identifying duplicates to synchronizing data. While Windows offers some built-in comparison features, they often lack the comprehensive functionality required for detailed analysis. This article presents a robust command-line script solution to efficiently compare two directory trees based on file and folder paths, as well as file sizes.

Using a Command-Line Script for Comprehensive Comparison

This method utilizes a batch script (ccomp.cmd) that leverages the Windows command-line interface for powerful and customizable file comparison.

1. Creating the Script:

Save the following code as ccomp.cmd in a location accessible through your system’s PATH environment variable:

@echo off
if "!ERRORLEVEL!" == "%ERRORLEVEL%" (
  REM if delayed expansion is enabled:
  (
    echo.
    echo ERROR: This script must be called in a Disabled Delayed Expansion block (default)!
    echo.
    call :PressAKey "Press a key to exit..."
    echo.
  )>con
  exit /b 1
)

setlocal disabledelayedexpansion

if defined _first_time goto :label1MAIN

REM Test CHCP:
chcp /?>nul 2>nul||(
  (
    echo. & echo ERROR: Could not start chcp (necessary)!
  )>con
  exit /b 1
)

REM Get the initial code page:
call :GetCurrentCodePage _initial_CP

REM Change the code page (character encoding) for "CON" (console) to 65001 (UTF-8):
set _con_error=false
mode con cp select=65001>nul 2>nul||(
  (
    echo. & echo WARNING: Could not change the code page for CON (Console)!
  )>con
  set _con_error=true
)

... (rest of the script code as provided in the original article) ...

2. Running the Script:

Open a command prompt and navigate to the directory where you saved ccomp.cmd. Execute the script using the following syntax:

ccomp <directory_1> <directory_2>

Replace <directory_1> and <directory_2> with the actual paths of the folders you want to compare.

3. Understanding the Output:

The script will output a detailed comparison highlighting:

• Files and folders unique to each directory: Indicating items present only in one of the two folders.
• Files with identical names but different sizes: Identifying potential discrepancies in content even when file names match.
• Files with size differences: Specifying which file is larger or smaller.

4. Important Considerations:

• Hidden Files with Unicode Paths: The script compares these files by path only, not by size, due to limitations in handling certain Unicode characters.
• Potential for Misreporting: In rare cases with complex Unicode file paths, some files might be misreported.
• Performance: The script utilizes the sort utility, so comparison time depends on the number of files being processed (time complexity is proportional to n*log(n)). For very large directories, consider using specialized file comparison tools.

This script provides a comprehensive solution for comparing files in two folders on Windows 10. Its command-line nature allows for automation and integration into more complex workflows. While it offers significant advantages over basic Windows tools, remember the limitations regarding hidden files with Unicode paths. Always verify crucial results using alternative methods if necessary.