Batch script (.bat) realizes real-time monitoring of folders and executing commands [if there is a new file, copy it to the remote folder]

Think of a scene. The program monitors the folder situation in real time. If a new file enters, analyzes its file name, and then performs corresponding operations if the preset conditions are met. For example, if the scanner scans a file, it will save the new file into a specific folder, and you can use this program to process it.

The most direct way to use .bat batch processing on the Windows side is to use Powershell or C# or python language platforms to be easier and more professional, so .bat is implemented here. The author likes itblackUnder the window, I looked at the feeling of printing out strings one by one, haha~~~

【Design Requirements】

【Design idea】

1. To monitor whether there are new files in the folder, you need to compare the current file list with the previous file list. If there are differences, add or delete files.

2. Record the new file name, parse the characters and compare them to obtain a file object that meets the conditions.

3. Copy the files that meet the conditions to a remote folder. Among them, remote communication requires both parties to enable sharing.

4. Each key operation needs to be summarized as descriptive characters and written to the log file.

5. The program needs to have a dead loop mechanism to keep monitoring, and Ctrl+C can exit.

【Design script】

First, define the necessary variables:

set "script_dir=%~dp0" %Define the current script directory %
 set "target_dir=D:\projects\cmd\targetdir" %Define the directory address of the monitored %
 set "remote_dir=\\DESKTOP-JL8BQNM\temp4share" %Define the remote directory address%
 set "log_file=%script_dir%" %log file storage address %
 set "check_interval=5" %Re-execution interval 5 seconds%

Then write the cmd interface and give necessary explanations:

echo =================================================================
 echo █ File monitoring and transfer tool █
 echo =================================================================
 echo [version features]
 echo √ Strictly match files starting with capital A √ Special characters support
 echo √ Real-time transmission status prompt √ Detailed logging
 echo Monitoring Directory: "%target_dir%"
 echo remote directory: "%remote_dir%"
 echo log file: "%log_file%"
 echo detection interval: per %check_interval% seconds
 echo =================================================================
 echo [Note] Monitoring will be paused when large files are transferred, keeping the window open
 echo Press Ctrl+C to terminate the program safely
 echo =================================================================

Then, write the core algorithm:

:: Generate initial file snapshot
 dir /b "%target_dir%" > "%script_dir%"

Generate a file snapshot again and compare it with the previous one:

dir /b "%target_dir%" > "%script_dir%"
findstr /v /g:"%script_dir%" "%script_dir%" > "%script_dir%"

If there are new files, do the corresponding processing:

for /f "usebackq tokens=*" %%f in ("%script_dir%") do (
    call :process_file "%%~f"
)

Extract the initial letter of the file name:

set "first_char=!filename:~0,1!"

Then make a judgment. If the first letter "A" is in line with, then do a copy operation. If the file is not ignored:

if "!first_char!"=="A" (
     color 0A
     echo meets the criteria: file starting with capital A
     echo starts transfer, do not close the window...
    
     :: Use robocopy to enhance transfer (display progress but keep silent)
     robocopy "%target_dir%" "%remote_dir%" "!filename!" /njh /njs /ndl /nc /np
    
     :: Error code handling (ROBOCOPY specific code)
     if errorlevel 8 (
         color 0C
         echo [Serious Error] Code!Errorlevel! Insufficient disk space
         echo [%timestamp%] ERROR: Transmission failed → "!safe_filename!" [Code!errorlevel!] >> "%log_file%"
     ) else if errorlevel 4 (
         color 0E
         echo [Warning] Code!errorlevel! File mismatch
         echo [%timestamp%] WARN: Transmission exception → "!safe_filename!" [Code!errorlevel!] >> "%log_file%"
     ) else if errorlevel 1 (
         color 0A
         echo [successful] Transmission completed
         echo [%timestamp%] SUCCESS: Transmitted → "!safe_filename!" >> "%log_file%"
     )
     color 0F
 ) else (
     echo Ignore: Files starting with non-caps A
     echo [%timestamp%] INFO: Ignore file → "!safe_filename!" >> "%log_file%"
 )

Because you want to generate a log, you get the time and enter it into .log for each operation.

:get_timestamp
for /f "tokens=2 delims==." %%t in ('wmic os get localdatetime /value 2^>nul') do set "datetime=%%t"
set "timestamp=!datetime:~0,4!-!datetime:~4,2!-!datetime:~6,2! !datetime:~8,2!:!datetime:~10,2!:!datetime:~12,2!"

In addition, if you want to continuously monitor, the program needs to be executed cyclically:

rem ...
 :: =================================================
 :monitor_loop
 call :get_timestamp

 rem ...

 :: interval detection (non-blocking waiting)
 timeout /t %check_interval% /nobreak >nul
 goto monitor_loop

There are some details:

Use the robocopy command to transfer:

robocopy "%target_dir%" "%remote_dir%" "!filename!" /njh /njs /ndl /nc /np /ns /nfl
 if errorlevel 8 (
     ...Error handling...
 )

It is more scientific and safer, improves the ability to handle special characters, and can also return error messages.

• ROBOCOPY Error Code Table：

Therefore, the error code can be compared one by one:

:: Error code handling (ROBOCOPY specific code)
     if errorlevel 8 (
         color 0C
         echo [Serious Error] Code!Errorlevel! Insufficient disk space
         echo [%timestamp%] ERROR: Transmission failed → "!safe_filename!" [Code!errorlevel!] >> "%log_file%"
     ) else if errorlevel 4 (
         color 0E
         echo [Warning] Code!errorlevel! File mismatch
         echo [%timestamp%] WARN: Transmission exception → "!safe_filename!" [Code!errorlevel!] >> "%log_file%"
     ) else if errorlevel 1 (
         color 0A
         echo [successful] Transmission completed
         echo [%timestamp%] SUCCESS: Transmitted → "!safe_filename!" >> "%log_file%"
     )

besidesSpecial characters &Handling

set "safe_filename=!filename:^&=^^^&!"

Avoid special characters in file names. (In fact, as a file name, special characters are not allowed, so it is used for insurance here)

in addition：

@echo off: Turn off command echo to improve the cleanliness of the interface

setlocal enabledelayedexpansion: Enable delayed variable extension, handle dynamic variables correctly, always use at the beginning of the scriptsetlocalPrevent environmental variables of the system

title: Customize the console window title

color 0F & cls: Set white text and clear content

Also always pay attention to log backup information. like:

echo [%timestamp%] INFO: Discover file → "!safe_filename!" >> "%log_file%"

Complete script codeas follows:

@echo off
 setlocal enabledelayedexpansion
 title file monitoring and transfer tool V1.4

 :: ============================================================
 set "script_dir=%~dp0" & rem Get the directory where the script is located
 set "target_dir=D:\projects\cmd\targetdir" & rem Monitoring Directory
 set "remote_dir=\\DESKTOP-JL8BQNM\temp4share" & rem Remote Directory
 set "log_file=%script_dir%" & rem log file path
 set "check_interval=5" & rem Detection interval (seconds)

 :: =========================== Initialization interface ===========================
 color 0F & cls
 echo =================================================================
 echo █ File monitoring and transfer tool █
 echo =================================================================
 echo [version features]
 echo √ Strictly match files starting with capital A √ Special characters support
 echo √ Real-time transmission status prompt √ Detailed logging
 echo Monitoring Directory: "%target_dir%"
 echo remote directory: "%remote_dir%"
 echo log file: "%log_file%"
 echo detection interval: per %check_interval% seconds
 echo =================================================================
 echo [Note] Monitoring will be paused when large files are transferred, keeping the window open
 echo Press Ctrl+C to terminate the program safely
 echo =================================================================

 :: ====================== File list initialization =======================
 dir /b "%target_dir%" > "%script_dir%"

 :: =================================================
 :monitor_loop
 call :get_timestamp
 echo [%timestamp%] Scan in progress...

 :: Generate the current file list (safe mode)
 dir /b "%target_dir%" > "%script_dir%"

 :: Detect new files (enhanced mode)
 findstr /v /g:"%script_dir%" "%script_dir%" > "%script_dir%"

 :: Process new files (supports special characters)
 for /f "usebackq tokens=*" %%f in ("%script_dir%") do (
     call :process_file "%%~f"
 )

 :: Update file list cache
 move /y "%script_dir%" "%script_dir%" >nul
 del "%script_dir%" 2>nul

 :: interval detection (non-blocking waiting)
 timeout /t %check_interval% /nobreak >nul
 goto monitor_loop

 :: ======================= File Processing Module ========================
 :process_file
 set "filename=%~1"
 set "safe_filename=!filename:^&=^^^&!" & rem escapes special characters

 :: Get the first character (ASCII value method is more reliable)
 set "first_char=!filename:~0,1!"
 call :get_timestamp

 :: Logging (double write)
 echo [%timestamp%] File found: "!safe_filename!"
 echo [%timestamp%] INFO: Discover file → "!safe_filename!" >> "%log_file%"

 :: ============= Strict capital A detection (ASCII value 65) =============
 if "!first_char!"=="A" (
     color 0A
     echo meets the criteria: file starting with capital A
     echo starts transfer, do not close the window...
    
     :: Use robocopy to enhance transfer (display progress but keep silent)
     robocopy "%target_dir%" "%remote_dir%" "!filename!" /njh /njs /ndl /nc /np
    
     :: Error code handling (ROBOCOPY specific code)
     if errorlevel 8 (
         color 0C
         echo [Serious Error] Code!Errorlevel! Insufficient disk space
         echo [%timestamp%] ERROR: Transmission failed → "!safe_filename!" [Code!errorlevel!] >> "%log_file%"
     ) else if errorlevel 4 (
         color 0E
         echo [Warning] Code!errorlevel! File mismatch
         echo [%timestamp%] WARN: Transmission exception → "!safe_filename!" [Code!errorlevel!] >> "%log_file%"
     ) else if errorlevel 1 (
         color 0A
         echo [successful] Transmission completed
         echo [%timestamp%] SUCCESS: Transmitted → "!safe_filename!" >> "%log_file%"
     )
     color 0F
 ) else (
     echo Ignore: Files starting with non-caps A
     echo [%timestamp%] INFO: Ignore file → "!safe_filename!" >> "%log_file%"
 )

 echo --------------------------------------------------------
 exit /b

 :: ====================== Timestamp generation module =========================
 :get_timestamp
 for /f "tokens=2 delims==." %%t in ('wmic os get localdatetime /value 2^>nul') do set "datetime=%%t"
 set "timestamp=!datetime:~0,4!-!datetime:~4,2!-!datetime:~6,2!!datetime:~8,2!:!datetime:~10,2!:!datetime:~12,2!"
 exit /b

 endlocal

【Design summary】

The program can also be optimized later, such as introducing configuration files ----, such as:

[Settings]
TargetDir=D:\projects\cmd\targetdir
RemoteDir=\\DESKTOP-JL8BQNM\temp4share
CheckInterval=5

Also, for escape algorithms, in order to handle file names,&character:

set "safe_filename=!filename:^&=^^^&!"

Of course, this operation is only escaped.&Symbols, other special characters such as|、>、<Additional processing is still required.

However, under normal circumstances, special characters should not appear in file names, so there is no need to go into it.

And for:

for /f "usebackq tokens=*" %%f in ("%script_dir%") do (

To prevent backticks and brackets from causing interference to text processing.

usebackqThe parameters are for the normal processing of backtick marks."%script_dir%", plus double quotes to prevent brackets from being parsed as part of the command. It is recommended that all path operations force quotation wrapping to avoid parsing errors.

OKoptimizationPart:

1. TemporaryThe file can be eliminated without displaying it and before exiting the program.

2. The copy file is actually the blocking program continues to monitor, and if possible, set it to non-blocking.

3. Set up log rotation to manage logs more scientifically.

ShouldscriptIt can be used as a lightweight solution case, showing the implementation paradigm of real-time monitoring logic, and providing a basic design pattern reference for the development of complex systems. Hope to give readers some inspiration.CMD, your dad will always be your dad~~~~