(.bat, .py, .sh, .ps1) - This script generates a file that contains the contents of all files in a directory and its subdirectories. Great tool for using with ChatGPT - so you can export all your files quickly and paste it over! Powershell version is the most customized for now.

GenerateFileContents.bat

:: GenerateFileContents.bat
:: ~~~~~~~~~~~~~~~~~~~~~~~~
:: Description:
::   This script generates a file that contains the contents of all files in a directory and its subdirectories.
::
:: Parameters:
::   1. Directory path to search for files in (i.e. "D:\Other\Java Projects\luhnalgorithm\src\main\java\com")
::   2. Output file path (i.e. "D:\Other\Java Projects\luhnalgorithm\filecontents.txt")
::   3. File extensions to look for (i.e. "java" or "java txt" or "java txt csv")
::
:: Usage:
::   .\GenerateFileContents.bat "D:\Other\Java Projects\luhnalgorithm\src\main\java\com" "D:\Other\Java Projects\luhnalgorithm\filecontents.txt" "java txt csv"
::
:: Author: CodeByAidan (https://github.com/CodeByAidan)
:: Date: 02-26-2024
:: ~~~~~~~~~~~~~~~~~~~~~~~~

@echo off
setlocal enabledelayedexpansion
setlocal enableextensions

rem Directory path is the first argument
set "directory=%~1"

rem Output file path is the second argument
set "outputFile=%~2"

rem File extensions to look for are the third argument
set "extensions=%~3"

rem Delete the output file if it already exists
if exist "%outputFile%" del "%outputFile%"

rem Perform the main loop
call :mainLoop

rem Remove the {REMOVE-ME} lines
powershell -Command "(Get-Content '%outputFile%') -replace '{REMOVE-ME}', '' | Set-Content '%outputFile%'"

rem Inform user about the completion
echo File contents have been written to "%outputFile%"

rem Exit the script
exit /b

rem This function iterates through the files in the directory and subdirectories
:mainLoop
for %%E in (%extensions%) do (
    for /r "%directory%" %%F in (*.%%E) do (
        rem Call the function that writes to the output file
        call :writeToFile "%%F"
    )
)
exit /b

rem This function writes the file's content to the output file
:writeToFile
    set "fullPath=%~1"
    set "relativePath=!fullPath:%directory%\=!"

    rem Output file title
    >>"%outputFile%" echo !relativePath!
    >>"%outputFile%" echo ======

    rem Output file contents
    type "%fullPath%" >> "%outputFile%"

    rem Add newlines for separation
    >>"%outputFile%" (echo {REMOVE-ME})
    >>"%outputFile%" (echo {REMOVE-ME})
exit /b

GenerateFileContents.ps1

<#
.SYNOPSIS
    This script recursively searches a directory and its subdirectories for
    files with specified extensions and compiles their contents into a single
    output file, excluding specified files.

.DESCRIPTION
    This script generates a file that contains the contents of all files in
    a directory and its subdirectories, excluding specified files. It searches
    the specified directory and its subdirectories for files with the specified
    extensions and compiles their contents into a single output file. Optionally,
    specific files can be excluded from the output. Additionally, it can include
    a directory tree at the end of the file.

.PARAMETER Directory
    Directory path to search for files in.

.PARAMETER OutputFile
    Output file path.

.PARAMETER Extensions
    File extensions to look for.

.PARAMETER ExcludeFiles
    Files or patterns to exclude from the output. Wildcards (*) are supported.
    The current directory can be specified using ".\".

.PARAMETER IncludeTree
    Switch to include a directory tree at the end of the output file.

.EXAMPLE
    .\GenerateFileContents.ps1 -Directory "$pwd\src" -OutputFile "$pwd\filecontents.txt" -Extensions "java", "txt" -ExcludeFiles ".\filecontents.txt", "*.tmp", "LOL.txt", ".\Hello.txt" -IncludeTree True
    .\GenerateFileContents.ps1 -Directory "$pwd" -OutputFile "$pwd\filecontents.txt" -Extensions "java", "txt" -ExcludeFiles ".\filecontents.txt", "*.tmp", "LOL.txt", ".\Hello.txt"
    .\GenerateFileContents.ps1 -Directory "$pwd" -OutputFile "$pwd\filecontents.txt" -Extensions "java", "txt" -ExcludeFiles ".\filecontents.txt", "*.tmp", "LOL.txt"
    .\GenerateFileContents.ps1 -Directory "$pwd" -OutputFile "$pwd\filecontents.txt" -Extensions "java", "txt" -ExcludeFiles ".\filecontents.txt"
    .\GenerateFileContents.ps1 -Directory "$pwd" -OutputFile "$pwd\filecontents.txt" -Extensions "java", "txt"

.NOTES
    Author: CodeByAidan (https://github.com/CodeByAidan)
    Date: 02-26-2024
#>


param (
    [string]$Directory,
    [string]$OutputFile,
    [string[]]$Extensions,
    [string[]]$ExcludeFiles,
    [switch]$IncludeTree
)

# Function to resolve files specified in the .\filename.txt format
function ResolveRelativePath($File) {
    $currentDirectory = (Get-Item -Path ".\").FullName
    return Join-Path -Path $currentDirectory -ChildPath $File
}

# Resolve files specified in the .\filename.txt format
$ResolvedExcludeFiles = @()
foreach ($ExcludeFile in $ExcludeFiles) {
    if ($ExcludeFile -like ".\*") {
        $ResolvedExcludeFiles += ResolveRelativePath -File $ExcludeFile.Substring(2)
    } elseif ($ExcludeFile -like "*.*") {
        $ResolvedExcludeFiles += ResolveRelativePath -File $ExcludeFile
    } else {
        $ResolvedExcludeFiles += $ExcludeFile
    }
}

# Remove the output file if it already exists
if (Test-Path $OutputFile) {
    Remove-Item $OutputFile
}

# Process files based on the specified extensions and excluding the specified files
foreach ($Extension in $Extensions) {
    Get-ChildItem -Path $Directory -Recurse -Filter "*.$Extension" | ForEach-Object {
        if ($_.FullName -ne $OutputFile -and $_.FullName -notin $ResolvedExcludeFiles) {
            Add-Content -Path $OutputFile -Value $_.FullName
            Add-Content -Path $OutputFile -Value "======="
            Get-Content $_.FullName | Add-Content -Path $OutputFile
            Add-Content -Path $OutputFile -Value "{REMOVE-ME}"
            Add-Content -Path $OutputFile -Value "{REMOVE-ME}"
        }
    }
}

# Remove the {REMOVE-ME} lines from the output file
(Get-Content $OutputFile) -replace "{REMOVE-ME}", "" | Set-Content $OutputFile

# Include tree if the switch is provided
if ($IncludeTree) {
    Add-Content -Path $OutputFile -Value "`nTree Directory`n============"
    $treeOutput = tree . /F | Select-Object -Skip 2 | ForEach-Object { $_.TrimEnd() }
    $treeOutput | Out-File -FilePath $OutputFile -Append -Encoding utf8
}

Write-Host "File contents have been written to $OutputFile"

GenerateFileContents.py

r"""
GenerateFileContents.bat
~~~~~~~~~~~~~~~~~~~~~~~~
Description:
  This script generates a file that contains the contents
  of all files in a directory and its subdirectories.

Parameters:
  1. Directory path to search for files in (i.e.
    "D:\Other\Java Projects\luhnalgorithm\src\main\java\com")
  2. Output file path (i.e.
    "D:\Other\Java Projects\luhnalgorithm\filecontents.txt")
  3. File extensions to look for (i.e. "java" or "java txt"
    or "java txt csv")

Usage:
    python GenerateFileContents.py <directory> <output_file> <extensions>
    ex. python GenerateFileContents.py "D:\Other\Java Projects\luhnalgorithm\src\main\java\com" "D:\Other\Java Projects\luhnalgorithm\filecontents.txt" "java txt csv"

Author: CodeByAidan (https://github.com/CodeByAidan)
Date: 02-26-2024
~~~~~~~~~~~~~~~~~~~~~~~~
"""

from typing import List, TextIO
import os


def main(directory: str, output_file: str, extensions: List[str]) -> None:
    """
    Deletes the output file if it already exists, performs the
    main loop to write file contents to the output file, and
    informs the user about the completion.

    Args:
        directory (str): The directory to search for files.
        output_file (str): The path of the output file.
        extensions (List[str]): The list of file extensions to search for.

    Returns:
        None
    """
    # Delete the output file if it already exists
    if os.path.exists(output_file):
        os.remove(output_file)

    # Perform the main loop
    with open(output_file, "a", encoding="utf-8") as f:
        for root, _, files in os.walk(directory):
            for file in files:
                if file.endswith(tuple(extensions)):
                    write_to_file(os.path.join(root, file), f)

    # Inform user about the completion
    print(f"File contents have been written to '{output_file}'")


def write_to_file(file_path: str, output_file: TextIO) -> None:
    """
    Writes the contents of a file to the output file.

    Args:
        file_path (str): The path of the file to be written.
        output_file: The output file object to write to.

    Returns:
        None
    """
    # Output file title
    output_file.write(file_path + "\n")
    output_file.write("=====\n")

    # Output file contents
    with open(file_path, "r", encoding="utf-8") as f:
        output_file.write(f.read())

    # Add newlines for separation
    output_file.write("\n\n")


if __name__ == "__main__":
    import sys

    if len(sys.argv) != 4:
        print(
            "Usage: python generate_file_contents.py <directory> <output_file> <extensions>"
        )
        sys.exit(1)
    main(sys.argv[1], sys.argv[2], sys.argv[3].split())

GenerateFileContents.sh

#!/bin/bash

# Description:
#   This script generates a file that contains the contents of all files in a directory and its subdirectories.
#
# Parameters:
#   1. Directory path to search for files in (i.e. "/mnt/d/Other/Java Projects/luhnalgorithm/src/main/java/com")
#   2. Output file path (i.e. "/mnt/d/Other/Java Projects/luhnalgorithm/filecontents.txt")
#   3. File extensions to look for (i.e. "java txt csv")
#
# Usage:
#   ./GenerateFileContents.sh "/mnt/d/Other/Java Projects/luhnalgorithm/src/main/java/com" "/mnt/d/Other/Java Projects/luhnalgorithm/filecontents.txt" "java txt csv"
#
# Author: CodeByAidan (https://github.com/CodeByAidan)
# Date: 02-26-2024

# Directory path is the first argument
directory="$1"

# Output file path is the second argument
outputFile="$2"

# File extensions to look for are the third argument
extensions="$3"

# Delete the output file if it already exists
[ -f "$outputFile" ] && rm "$outputFile"

# Perform the main loop
for ext in $extensions; do
    find "$directory" -type f -name "*.$ext" | while read -r file; do
        # Write the file's content to the output file
        relativePath="${file#$directory/}"
        echo "$relativePath" >> "$outputFile"
        echo "=======" >> "$outputFile"
        cat "$file" >> "$outputFile"
        echo "" >> "$outputFile"
        echo "" >> "$outputFile"
    done
done

# Inform the user about the completion
echo "File contents have been written to $outputFile"

DEMO:
https://gist.github.com/assets/67598470/59296e33-14b2-407b-a7e1-9c3f8f04dd74