Normally, deleting directories is a fairly quick process when they contain a modest number of sub-directories and files. However, when directories have complex structures consisting of hundreds or thousands of sub-directories and files, it can take several minutes or even hours to delete them. The command line, with less overhead, can delete complex directories in a fraction of that time, often quoted as being 20 times or more faster than using the traditional explorer option. This guide demonstrates how to automate the deletion of large directories with batch files, from the command line using native Windows commands and tools, and with selected freeware GUI deletion programs that include a command line option. Tthe various deletion tools covered in this guide are also tested and compared in the last section. The emphasis of this guide is on the quick deletion methods and not on secure or permanent deletion methods that are normally used to make files unrecoverable. Secure deletion methods are another topic and are necessarily slower since they involve overwriting files, often using several passes.

Explorer can be extremely slow when deleting directories because it calculates the folder size, the number of items in the folder, the estimated completion time before processing, and monitoring and reporting on items deleted, remaining deletions, current deletions, and conflicts during processing. These processes are still in effect even when the recycle bin is emptied or when files and folders are deleted directly using Shift+Del. Using the command line can eliminate this overhead, resulting in a faster deletion process. Keep in mind that faster means relative to the standard deletion process, so deleting several Gigabytes of files and directories may still take a significant amount of time. For example, tests performed by a SuperUser member found that it took an average of 53 minutes to delete 28.3 GB consisting of 1,159,211 files in 146,918 folders using the fastest command line method tested (a combination of the DEL and RMDIR commands). If files and folders are to be deleted on a regular basis, probably the fastest method is to save them to a dedicated partition and then to format that partition to delete everything.

Commands

Although the RMDIR command can remove a directory and its files, it’s significantly slower than using the DEL and RMDIR commands in a two-step process. The DEL command deletes the files, and the RMDIR command deletes the directory structure.

del /f/q/s "%folder%" >nul

Acts as a first pass to delete files and outputs to nul to avoid the overhead of writing to the screen

rmdir /q/s "%folder%"

2nd pass that removes the directory structure

• /f – Force delete read-only files
• /q – Quiet mode, do not ask to delete
• /s – Include subdirectories

RoboCopy

Another method for deleting folder files is RoboCopy. A destination folder is mirrored from an empty source directory, which forces RoboCopy to delete any files not in the source directory.

The main command for RoboCopy to delete all files in the destination directory:

robocopy "SomeEmptyDir" "DestinationDir" /MIR /W:0 /R:0

• /MIR – Mirror a directory
  
• /W:0 – Sets wait time between retries to zero secs
  
• /R:0 – Sets number of retries on failed copies to zero secs

RoboCopy works with directories and sets of files within directories as opposed to individual files. In the provided example batch files using RoboCopy, RMDIR is still used to remove the temporary empty directory and the parent destination directory, and DEL is used for deleting files.

Using Batch Files

Batch files, including the example files below, may be used from the command line (with parameters), from the send-to directory, the right-click context menu, or by drag and drop (the easiest method).

Command line

The batch files may be executed from a Windows command prompt with parameters, or added to the environmental path for convenience.

To execute from a command prompt, open a new cmd prompt, navigate to the batch file’s location and enter its full name, or enter the batch file’s full path. Be sure to add the directories and/or files to delete as parameters. Also include quotes around any file paths with spaces:

Ex. “C:\Program Files\delete_file_folder_fast_simple_v2.bat” “C:\Folder or file to delete”

Separate multiple parameters with a space between parameters.

Adding a batch file’s folder to the Windows environment variable allows it to be available from any cmd prompt without navigating to the batch file’s location or typing its full path. To add a batch file’s path to the Windows environment use:

start–> Control Panel–> System–> Advanced system settings–> Advanced Tab–> Environment Variables–> System Variables–> Path–> Edit.

Add the path e.g., ;C:\path to the batchfile; to the end (don’t forget the single semicolons at the beginning and end). Hit OK three times.

Right-click Context Menu

This option allows the user to right-click a folder and select the batch file from the pop-up menu. The steps to enable this are:

1. Press the WINDOWS KEY + R to open the Run dialog box
2. Enter regedit and press ENTER
3. Navigate to HKEY_CLASSES_ROOT\Directory\shell\
4. Right-click on the yellow shell key. Select New > Key
5. Enter a name: Delete &Fast then press ENTER
6. Right-click on the Delete &Fast folder created, and select New > Key
7. Enter “command” and press ENTER.
8. Left-click on the yellow command key created. Double-click the (Default) entry.
9. In the Value Data field, enter the batch file to use, e.g., cmd /c \”C:\\Path to\\delete_file_folder_fast_simple_v2.bat\” %1″ then press OK

Another way to accomplish the above is to use a reg file. Copy the code below, paste it into a file editor and save it as “Delete Fast.reg”. Double click the file to merge its contents to the registry and the right-click menu is ready to use.

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\Directory\shell\Delete &Fast\command]
@="cmd /c \"C:\\Path to\\delete_file_folder_fast_simple_v2.bat\" %1"

Send to Directory

Another option is the Sendto directory, Just create a shortcut and add it to the appropriate directory:

For newer versions of Windows, the send to directory is located at:

C:\Users\<yourusername>\AppData\Roaming\Microsoft\Windows\SendTo

For XP, the location is:

C:\Documents and Settings\<yourusername>\SendTo

To use, right click a file or directory and select the batch file from the Send to menu.

Drag and Drop

The easiest way to use the example batch files is to just drag and drop folders or files onto them. No files or folders will be deleted without user confirmation.

Differences in the Example Batch Files

delete_files_folders_fast_v2.bat – lists multiple files and folders to be deleted, the parent directory, limited folder/file attributes, and limited information on the names and numbers of files and folders deleted. Also includes a delayed exit, allowing the files and folders deletion information to be reviewed before the window closes (default 10 seconds).

delete_file_folder_fast_simple_v2.bat – limited to deleting one file or one folder at a time. Doesn’t provide much interaction or feedback except to ask  the user if they actually want to delete the displayed file or folder. Automatically exits after deleting the file or folder.

delete_files_folders_fast_robocopy_v3.bat – essentially the same as delete_file_folder_fast_simple_v2.bat except that RoboCopy’s output is displayed during execution and after processing files. The batch file is paused after execution allowing the user to view the results without automatically exiting. Updated 01-29-20.

delete_files_folders_fast_robocopy_silent_v3.bat – essentially the same as above except that RoboCopy’s output is NOT displayed for faster execution and processing. The batch file automatically exits after a delay of 10 seconds. Added 01-29-20.

delete_file_folder_fast_simple_robocopy_v2.bat – limited to deleting one file or one folder at a time.Uses RoboCopy instead of DEL for deleting folder contents. RoboCopy output is redirected to nul to eliminate command output. Automatically exits after deleting the file or folder.

delete_file_folder_fast_byenow_v1.bat – uses command line program byenow to delete a folder and all of its files and subdirectories.Uses byenow’s default settings. Batch file pauses on completion.

delete_file_folder_fast_byenow_ntapi_v1.bat – uses command line program byenow to delete a folder and all of its files and subdirectories. Same as previous batch file but uses –delete-ntapi option. Batch file pauses on completion.

The batch files may be renamed and will work identically.

Example Batch Files using DEL, RMDIR, and RoboCopy

Left-click to view the file in the current window, or use right-click and “Save Link As” to download.The batch files are changed from the previous versions as the /S switch greatly slowed performance when deleting individual files. The /S switch is still used, but only for folders.
Note: Remove the “.txt” extension before using.

The batch files below use only the RMDIR and DEL commands.

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The below batch files use RoboCopy to delete folder files, RMDIR to delete  empty folders, and DEL to delete individual files. If RoboCopy is installed but not included in the Windows environment path, be sure to change the path for RoboCopy for your system in the batch file (don’t forget to remove the REM to enable it). No changes to the batch files are required if RoboCopy is already installed and included in the path. To check, type “robocopy: in a command prompt. If RoboCopy executes, it’s already installed and included in the environment path.

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Freeware Deletion Tools

A number of GUI and command line file and folder deletion tools are available, but most focus on secure deletions and don’t provide an option for standard deletions. The freeware utilities below are able to perform both standard and secure deletions from the GUI and from the command line.

These GUI-based tools work from the command line either through the main executable for by using separate command line executables. The advantage of using these tools rather than using native windows commands like RMDIR and DEL is that it’s easier to configure complex deletion options such as deleting files or folders based on modification or creation date, size, or type, as well as to write logs, send the process to background, set automatic system shutdowns, exclude/include specific files and folders, stop on errors, and set many other options using  a single command line.

FastCopy

FastCopy is a copy/backup utility that can also perform standard and limited secure deletions on individual files and folders. It can be installed as a regular program or as a portable application by selecting extract during installation. The program executable also accepts commands from the command line.

Files and folders can be dropped and dragged onto the interface to set the source or destination directories. From the Options menu, the program can be configured to install shell extensions to enable FastCopy to delete, copy, or move files/folders by using the right click menu in Windows Explorer.

FastCopy Interface

FastCopy Delete Options

FastCopy Shell Extension Options

FastCopy Command line and Batch File

A listing of FastCopy’s command line options can be found online help page and in the application’s help file. The below batch file is configured to delete files and folders using drag and drop with two options: (1) Do NOT ask for confirmation before deleting and disable logging, and (2) Ask for confirmation before deleting and enable logging. The batch file pauses after execution. The batch file is configured to use a portable installation.

The breakdown of the first FastCopy command line (no confirmation, no logging):

FastCopy.exe /cmd=delete /no_confirm_del /log=FALSE /auto_close %*

• /cmd=delete – delete command
  
• /no_confirm_del – Don’t confirm before deleting
  
• /log=FALSE – Disable write operation/errors information to the logfile
• /auto_close – Close automatically after execution is finished with no errors
  
• %* – All dragged and dropped files and folders
  

Example Batch File for FastCopy (remove .txt extension before using):

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Fast Folder Eraser Pro

Fast Folder Eraser Pro is an installed freeware program. It can perform both standard and secure deletions both from the command line or from the GUI interface. The standalone command line executables are located in the command-line folder which contains two CLI executables, a 32-bit version and a 64-bit version.

This is a utility specifically designed to delete directories and the sub-folders and files within them. Unlike FastCopy, it’s unable to delete individual files by filename, but it’s able to delete individual or groups of files based on size, dates, and other filters, and it can exclude files using wildcards. Although folders and files can be directly dragged and dropped onto the GUI interface for deletion, testing revealed that when a file was dropped on the GUI, the program also deleted every other file and folder within the same directory as the dropped file. There were no issues with folders dropped onto the GUI or deleted using the CLI executable. The CLI executable is unable to delete individual files and generates an error if an individual file path is used with the delete command.

Compared to FastCopy, the number of command line options is limited. For example, no option exists to enable or disable confirmation before deleting a file, so a confirmation option must be programmed into the batch script using Windows commands to obtain this functionality.

Fast Folder Eraser Pro Interface

Fast Folder Eraser Pro Delete Options

Fast Folder Eraser Pro Command line and Batch File

The help file for the standalone CLI executables is located in the command-line folder along with two executables, a 32-bit CLI executable, FFECmd32.exe, and a 64-bit executable, FFECmd64.exe. The batch file below is configured for drag and drop using the 32-bit executable, includes confirmation before deletion, and pauses after execution.. Unlike FastCopy where multiple files and folders can be processed using a single command, the CLI executable in Fast Folder Eraser Pro is able to process only a singe folder at a time. If multiple folders are dragged and dropped onto the batch file, folders after the first are ignored. If a file or multiple files are dropped onto the batch file, the files are not processed.

The breakdown of the Fast Folder Eraser Pro command line as used in the batch file:

FFECmd32.exe /path %* /r /logfail

• /path %* – absolute path of directory to initiate deletion
• /r – recurse child directories
• /logfail – log unsuccessful file deletions to a log file

Example Batch File for Fast Folder Eraser Pro (remove .txt extension before using):

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byenow Command Line Utility

byenow is a specialized command line tool specifically designed to delete files and directories under a single folder. It uses several strategies not found for other deletion tools to streamline and optimize the deletion process such as: (1) providing essential, but not verbose, processing information, (2) the option to suppress confirmation, (3) using all available CPU cores by default, and (4) the option to use the NtDeleteFile API instead of the standard deletion process (DeleteFile API) to delete files. The NtDeleteFile API is faster because it requires only a single syscall instead of the three syscalls needed by the standard DeleteFile API. byenow also displays the time required for the deletion process upon completion. Below is a summary listing of byenow’s user settable options:

• preview the number files and folders to be deleted
• set the number of threads (uses same number of threads as CPU cores by default)
• suppress confirmation
• list errors
• display progress on a single line
• staged deletion – scan folder 1st and then delete
• use NtDeleteFile API instead of the default DeleteFile API

byenow Options

byenow Preview

byenow Command line and Batch File

Because byenow is already optimized for file deletion using its default settings, and its options are settable from the command line, only a basic batch file is needed to launch the program in a command window. Two batch files are provided, one with default settings and the other using the NtDeleteFile API. Because byenow is a command line only program, be sure to set the path for byenow in the batch files.

The breakdown of the byenow command line (with NtDeleteFile API option):

byenow “%~1” –delete-ntapi

• –delete-ntapi – use NtDeleteFile API instead of DeleteFile API

Example Batch Files for byenow (remove .txt extension before using):

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Batch File Benchmarks

The batch files were compared by benchmarking them using the standard Windows deletion process as a baseline. Nine identical test directories were created, each comprised of 12255 files in 1599 directories, and totaling 1658MBs. Each batch file was timed using a timer and/or using the logged times where appropriate to measure how long it took them to delete the test directory.

*Time includes 0:40 secs to send the test directory to the Recycle Bin and 1 min and 17 secs to empty the Recycle Bin (0:40 + 1:17 = 1:57).

Conclusions

Most of the command line tools tested were faster than using Windows standard delete, especially when the time needed to empty the Recycle Bin was included. The fastest command line tools were nearly twice as fast as the Windows standard delete process that sends files to the Recycle Bin, and over 4 times faster than Windows when the time needed to empty the Recycle Bin was factored in. Suppressing output and disabling logging helped to improve the performance of the command line tools, but the most significant factor appears to be that all the command line tools directly delete files and don’t use the Recycle Bin. The tests suggest that any program that directly deletes files will automatically seem faster in comparison to the full Windows standard delete process, even when they are actually slower than the time Windows takes just to send deleted files to the Recycle Bin. So while command line tools are  faster than using Windows Explorer for deleting large directories and files, It appears that claims of increased deletion speeds by multiple factors are likely exaggerated, and a more realistic expectation is probably from 2-3 times faster – at least for the freeware tools tested.

The test machine used was a 1.86GHz 32-bit single core laptop with 2GB of RAM. Some of the programs, such as byenow, are designed to take advantage of multiple cores, so results could vary greatly depending on the hardware and OS used. Also, the test directories were not really representative of a “real world” situation as they were actually small, and most users are unlikely to use specialized deletion tools to occasionally delete directories of less than 3-4 GBs. Although useful as a “rough estimate”, a more realistic test scenario might be to test the various batch file commands on machines with upgraded OS and hardware, and using a larger and more complex directory structure of perhaps 50 GBs or more .

Summary of test limitations:
Test on multiple hardware and OS platforms
Use larger and more complex test directories
Test multiple times to compensate for machine state variation

Related Information and References:

Fastest Way to Delete Large Folders in Windows – Matt’s Repository

How to delete huge number of files on Windows – Superuser

Automate saving web images to a specified folder by copying image URLs to the clipboard using an AutoHotKey (AHK) script. Usually, the process to save a web image from a browser consists of: (1) right-click the image, (2) select “save picture as”, and (3) navigate to the folder to save the image. While usually acceptable for single images, this process can can be slow and tedious for multiple images.

AutoHotKey and Wget need to be installed for the script to work. The version of Wget used for this guide was wget-1.19.1_curl-7.52.1_win32_win64.7z, a portable package with Curl that includes the 32-bit and 64-bit versions of Wget, a ca certificate, localization, and a manual. The latest Wget windows binaries may also be downloaded from eternallybored.org.

The script was tested on a 32-bit version of Windows XP, using portable versions of AutoHotKey and Wget. The only modification needed for a portable installation of Wget is to set the path for the wget or wget64 executables in the script. The script will work without modification if Wget and AutoHotKey are already installed and the paths for AHK and Wget were set by the installer. Paths can be checked with the “set” command from a windows prompt, or by using Control Panel -> System -> Advanced Tab -> Environment Variables -> System Variables -> Path.

AHK Script Download

(Click to view, or right-click and use “save Link Target as” to download):

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Setup and Use:

Setup
Before using, enter the path to the wget or wget64 executable in the script if wget is not in the system path. Optionally, enter a full path to an icon file for the script. Also, the extension of the script must be changed from txt to ahk.

How to Use

1. Start the script with a double-click
2. Enter or paste an existing folder path to save downloaded images and click OK. If no path is entered the default path will be the same folder as the script.
3. Right click an image in your web browser and select “Copy image URL”
   1. A cmd window opens and displays downloading progress. It closes after the download is completed
   2. The image URL and date are appended to photolog.csv in the specified folder
   3. All characters after jpg. jpeg, gif, or png are removed from the URL before downloading
   4. URLs that don’t include the jpg, jpeg, gif, or png extensions are ignored
4. To change folders, reload the script and enter a new existing folder path

Context menu tools such as FilemenuTools may be used to start the script and set the download folder automatically from any location.

Finding the created, published or last modified date for web pages isn’t always as straightforward as it might appear. Although there are several ways to find the dates of web pages, none are 100% reliable, because regardless of the method used, no standard exists for dating web pages. The most authoritative way to find dates is from the page content itself, and even that has its shortcomings, since nothing requires dates to be accurate in the first place. In most cases, the best that can be achieved will be an approximation.

Some of the methods that can be used to find created, published, or modified dates for web pages are:

1. Web page content
2. HTTP Headers
3. Browser Plugins
4. Javascript in Address Bar
5. The Wayback Machine
6. Google Cache
7. RSS Feed

1. Web Page Content (preferred method when possible)

Pages often have a first published, updated, or posted date somewhere on the page. As mentioned, although this is the most accurate method, it still has its problems. An author could leave the date out, or use a wrong date – either intentionally or unintentionally. Even so, obtaining dates from web page content is the most accurate and authoritative method.

2. HTTP Headers

The Last-Modified field is an optional response field that reflects the date the origin server believes that the resource was modified. Because it is an optional field, it may or may not exist. Also, because no standard exists as to what the Last-Modified date field means, it’s often inaccurate or incorrect since that field also reflects any alterations made to the page, such as user comments or any changes other than the content.

3. Browser Plugins

There are browser plugins that can read a web page’s Last-Modified date field, but this method is still subject to the problems described for HTTP Headers above.

4. Javascript in Address Bar

This is a quick and easy way to retrieve the date from the site’s Last-Modifed date field in the HTTP Headers. To use it, just copy and paste the JavaScript string below to the address bar, or save it to a bookmark on your browser’s bookmark bar:

javascript:alert(document.lastModified)

Note: With dynamically generated content this will not work. Also, newer Internet browsers with an Omnibox require the user to manually type in javascript: even after they paste the entire string.

5. The Wayback Machine

The Way Back Machine was created by the nonprofit organization, the Internet Archive. It archives sites from the World Wide Web and other Internet information. There are a number of limitations to using this method including:

• not all pages on a site may be included
• not all sites are included. Webmasters can request that they not be included
• often it doesn’t include all changes made to web sites
• it may not be up-to-date. It can take several months for pages to appear
• user-defined dates cannot be specified, but only dates crawled by the Way Back Machine’s web crawler

6. Google Cache

Google Cache displays a web page when it was last crawled by Google. There are several problems with this method including:

• there isn’t a way to know the last time a page was crawled
• it isn’t possible to specify a date range of the cache
• changes to web sites are not tracked

To use Google Cache, enter the following into your web browser’s address bar, changing the name at the end of the URL to the site in question:

https://webcache.googleusercontent.com/search?q=cache:https://www.NameOfWebsite.com

7. RSS Feed

Many, but not all, sites include a RSS feed. If so, the published date for the page may be contained within its XML file. RSS XML files could have any name, but often use names such as index.xml or feed.xml. If it exists, it may be possible to view the file in a web browser to find dates. For further information, see Opening XML Files with a Browser. A simpler and easier option is to view the RSS feed for the page using a RSS feed reader.

Conclusion

If possible, the most authoritative and reliable method for finding the created, published, or modified dates is from the web page content. If dates don’t exist in the content, one or a combination of the above methods can be used to obtain approximate dates.

References:

Determine last modified date of a web page – Computer Hope

How do I find out when a web page was written? – Ask Leo

How to find out when a web page was created or updated – Maxi-Pedia

How to Know When a Web Page was Last Modified? – Infopackets

A handy reference source that provides FFMPEG command-line examples with breakdown as well as general information about video formats.

BugCodeMaster

Use 7-Zip

1. Open the 7-Zip file manager
2. Go to the folder of the long name file
3. Select the file, right click on it and select “rename”
4. Erase some of the words of the file and press enter

h/t ax_Cap

Source: TechPowerUp Forums

Cannot delete file or folder

Source: Windows Problem Solver Open information exchange

Where do I paste the code that I find on the internet

Source: Ron de Bruin Excel Automation

42+ Text-Editing Keyboard Shortcuts That Work Almost Everywhere

Source: How-to Geek

This guide demonstrates how to automate concatenating two or more audio files of the same format using FFmpeg while preserving the metadata in the merged file. A tested example batch file is provided to help illustrate. This guide is related to a previous post for concatenating audio files also with a batch file, but with using a different set of command-line tools for joining them.

What is FFmpeg?

FFmpeg is an open-source and cross-platform command-line set of SW programs for recording, converting and streaming audio and video. First developed under Linux, compiled versions are available for most operating systems and platforms. It has since become one of the best-known and most widely used products of its type. FFmpeg is compatible with a large number of SW applications and it’s used in many popular SW products such as VLC Media Player, YouTube, and Handbrake. Although FFmpeg includes over 100 codecs and a mind-boggling number of possible combined command-line options, it’s not that difficult to use.

To demonstrate how easy it can be, FFmpeg.org provides this example command for converting input.mp4 to output.avi on its homepage:

$ ffmpeg -i input.mp4 output.avi

While the above example is simple, FFmpeg commands can also be more complex.

Main FFmpeg Tools

The FFmpeg version used for this guide is a Windows complied version availiable from CODEX FFMPEG. Simply download the latest 32 or 64-bit static build from the builds page here and extract it to a folder (builds are compressed in 7z format). The version used was git-dee7440 (2015-11-01).

The FFmpeg package contains the following three main executable tools in the bin folder:

• ffmpeg.exe – a command-line encoder and media converter
• ffmprobe.exe – a command-line tool to analyze and display media information
• ffplay.exe – a simple media player

Note that there are a number of commands that are common between the three tools. Only ffmpeg.exe and ffmprobe.exe are used in this guide.

FFmpeg Help Files

FFmpeg provides three levels of help files: basic, long, and full. To view the commands available in the help files, click the ff-prompt.bat file in the root directory to open a command window or open your own in the bin folder and type in one of the following commands:

ffmpeg -h -- print basic options
ffmpeg -h long -- print more options
ffmpeg -h full -- print all options (including all format and codec specific options, very long

Here are links to the basic help file: ffmpeg_help and the full help file: ffmpeg_help_full. When printed to text, the help file sizes are: 5kB for the basic, 25kB for the full, and 487kB for the long help files. The long help file contains about 7,000 lines, which provides a hint as to how many commands are available.

Batch File

Batch file link: tasks_FFmpeg.bat

The link for the batch file used for this guide is provided above. Be sure to remove the txt extension before using it. The batch file is setup to work by the drag and drop method only.

To concatenate the audio files and write the metadata to the merged file, the batch file steps through the following:

1. Delete any previous metadata text files, listfiles, or json data files.
2. Write metadata for each audio file to a separate metadata text file
3. Write the filenames of the audio files to confiles.txt (see below format), a listfile FFmpeg uses to identify the audio files to concatenate
4. Concatenate the audio files and write the metadata from the first audio file’s metadata.txt file to the joined audio file.

For FFmpeg to use a listfile (confiles.txt), the filenames must be written to the confiles.txt file on separate lines using the following format.

file 'filename1.ext'
file 'filename2.ext'

The provided batch script should work for most audio formats of the same type provided they were encoded using the same codec (although they can be different containers). It was tested with opus, mp3, and aac files on a PC running Windows XP.

The batch script also provides options to separately print out audio file metadata, basic data, or stream and container (format) data to screen or to a file in json format (human readable form), with options to change the format in the script.

Command-Line Description

The main FFmpeg commands for extracting the metadata and concatenating the audio files are explained below. Although the ffprobe command was also used, it’s fairly simple to understand and should be self-explanatory by examining the code and the help files. The filenames used below are not actually in the batch script but have been simplified for explaination purposes.

The below command extracts and writes the metadata to a text file:

ffmpeg -i infile.ext -f ffmetadata metadatafile1.txt

• ffmpeg – calls ffmpeg
• -i infile.ext – specifies infile.ext as an input file
• -f ffmetadata metadatafile1.txt  – formats the metadata to file metadatafile1.txt

The metadata1.txt file is formatted as below:

;FFMETADATA1
album=Name of Album
artist=Artist Name
genre=Music Genre Name
title=Title Name
track=Track #
date=Date
encoder=Encoder Used

The next command is used to process mp3 files only. It concatenates the mp3 files and writes the metadatafile1.txt contents in id3 format of the first mp3 file to the merged mp3 file:

ffmpeg -f concat -i confiles.txt -i metadatafile1.txt -map_metadata 1 -id3v2_version 3 -write_id3v1 1 -c copy filename1_merged.mp3

• ffmpeg – calls ffmpeg
• -f concat -i confiles.txt – use concat demuxer to concatenate the mp3 files listed in confiles.txt (treats confiiles.txt as a single file and specifies it as input file 0)
• -i metadatafile1.txt – specify metadatafile1.txt as input file 1
• -map_metadata 1 – map input file 1 as the source for metadata (metadatafile1.txt)
• -id3v2_version 3 – select ID3v2 version 3 to write
• -write_id3v1 1 – enable ID3v1 writing
• -c copy filename1_merged.mp3 – stream copy to filename1_merged.mp3 (-c copy = stream copy)

The next command listed processes audio files other than mp3. It functions the same as the previous command but writes standard metadata (if present) from the first audio file to the merged file:

ffmpeg -f concat -i confiles.txt -i metadatafile1.txt -map_metadata 1 -c copy filename1_merged.ext

• ffmpeg – calls ffmpeg
• -f concat -i confiles.txt – use concat demuxer to concatenate the files listed in confiles.txt (treats confiiles.txt as a single file and specifies it as input file 0)
• -i metadatafile1.txt – specify metadatafile1.txt as input file 1
• -map_metadata 1 – map input file 1 as the source for metadata (metadatafile1.txt)
• -c copy filename1_merged.mp3 – stream copy to filename1_merged.ext (-c copy = stream copy)

Additional Help – Online Command-line Generators

There are a number of online FFmpeg command-line generators that can help construct various audio and video FFmpeg commands. A few of them are listed below:

FFmpeg Command Generator

References:

Useful FFmpeg Commands

Concatenating media files

FFprobeTips

FFmpeg & FFprobe Cheatsheet

FFmpeg Windows Binaries:

CodexFFMpeg

BtbN / FFmpeg-Builds

Command-line utilities are useful for expanding the capabilities of batch files. There are many more available, but the below list can be used as a starting point.

Free Command-line Utilities for Batch Scripts