Rename multiple files in a folder, add a prefix (Windows)

Batch Rename Files: Adding a Prefix in Windows

Learn how to efficiently add a prefix to multiple filenames in a Windows folder using PowerShell, a powerful scripting tool for system administration.

Renaming a single file is straightforward, but when you need to add a consistent prefix to dozens or even hundreds of files, manual renaming becomes tedious and error-prone. This article will guide you through using PowerShell, a command-line shell and scripting language built into Windows, to quickly and effectively batch rename files by adding a prefix. This method is invaluable for organizing documents, photos, or any collection of files that require a standardized naming convention.

Understanding the PowerShell Rename-Item Cmdlet

PowerShell's Rename-Item cmdlet is the core command we'll use for this task. It allows you to change the name of an item (like a file or folder). When combined with other cmdlets, such as Get-ChildItem (to list files) and a ForEach-Object loop, it becomes a powerful tool for bulk operations. The key to adding a prefix is constructing a new filename that includes both your desired prefix and the original filename.

flowchart TD
    A[Start] --> B["Get-ChildItem (List Files)"]
    B --> C{"For Each File"}
    C --> D["Construct New Name (Prefix + Original Name)"]
    D --> E["Rename-Item (Apply New Name)"]
    E --> C
    C --> F[End]

Flowchart of the batch renaming process using PowerShell.

Preparing Your Environment and Files

Before you begin, it's crucial to prepare your files and understand the process. Always work on a copy of your files first, especially when performing batch operations, to prevent accidental data loss. Identify the target folder and the specific prefix you want to add. PowerShell commands are case-insensitive for cmdlets but often case-sensitive for file paths and names, so pay attention to your input.

Step-by-Step Guide to Adding a Prefix

Follow these steps to add a prefix to all files within a specified folder. We'll use a simple PowerShell script that you can adapt to your needs.

1. Open PowerShell

Press Win + X and select 'Windows PowerShell' or 'Windows PowerShell (Admin)' from the menu. You can also search for 'PowerShell' in the Start menu.

2. Navigate to the Target Directory

Use the cd command to change your current directory to the folder containing the files you want to rename. For example, if your files are in C:\Users\YourUser\Documents\MyFiles, type: cd C:\Users\YourUser\Documents\MyFiles

3. Execute the Renaming Command

Once in the correct directory, use the following PowerShell command. Replace 'MyPrefix_' with your desired prefix and ensure the *.* matches the file types you want to target (e.g., *.txt for text files, *.* for all files).

Get-ChildItem -Path . -File | ForEach-Object {
    $newName = "MyPrefix_" + $_.Name
    Rename-Item -Path $_.FullName -NewName $newName
}

4. Verify the Renaming

After running the command, check the folder to ensure all files have been renamed correctly with the new prefix. You can use Get-ChildItem again in PowerShell or simply open File Explorer.

Get-ChildItem -Path "C:\Path\To\Your\Files" -File | ForEach-Object {
    $prefix = "ProjectA_"
    $newName = $prefix + $_.Name
    Rename-Item -Path $_.FullName -NewName $newName -WhatIf
}

# To execute the rename, remove '-WhatIf'
# Get-ChildItem -Path "C:\Path\To\Your\Files" -File | ForEach-Object {
#     $prefix = "ProjectA_"
#     $newName = $prefix + $_.Name
#     Rename-Item -Path $_.FullName -NewName $newName
# }

PowerShell script to add a prefix to all files in a specified directory. The -WhatIf parameter is used for a dry run.