How to Check if a File Exists and Rename it Using PowerShell?

Recently, I was working on a project for a client in New York where I needed to automate the process of checking for the existence of specific files and renaming them according to a predefined naming convention. You can do this easily with PowerShell scripts. In this tutorial, I will explain how to use PowerShell to check if a file exists and rename it with examples.

Now, let me show you how to check if a file exists and rename it using PowerShell with some real examples.

Check if a File Exists in PowerShell

PowerShell provides several methods to check if a file exists. I will show you two useful methods with examples.

1. Using Test-Path Cmdlet

The Test-Path cmdlet is the best way to check if a file exists in PowerShell. It returns $true if the file exists and $false if it doesn’t. Here’s an example:

$filePath = "C:\MyFolder\report.txt"
if (Test-Path $filePath) {
    Write-Host "The file exists."
} else {
    Write-Host "The file does not exist."
}

I executed the above PowerShell script using VS code, and you can see the exact output in the screenshot below:

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2. Using Get-Item Cmdlet

Another way to check if a file exists is by using the Get-Item cmdlet. If the file exists, it will return a FileInfo object; otherwise, it will throw an error. Here’s an example:

$filePath = "C:\MyFolder\MyPDFFile.pdf"
try {
    $file = Get-Item $filePath
    Write-Host "The file exists."
} catch {
    Write-Host "The file does not exist."
}

Get-Item is useful when retrieving additional information about the file, such as its size, creation time, or attributes.

Here is the exact output in the screenshot below:

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Rename a File in PowerShell

Once you have checked that a file exists, you might want to rename it. PowerShell provides the Rename-Item cmdlet for this purpose. Here’s an example:

$oldFilePath = "C:\MyFolder\sales_report.csv"
$newFilePath = "C:\MyFolder\sales_report_2024.csv"

if (Test-Path $oldFilePath) {
    Rename-Item $oldFilePath $newFilePath
    Write-Host "File renamed successfully."
} else {
    Write-Host "The file does not exist."
}

In this example, we first check if the file exists using Test-Path. If it does, we use the Rename-Item cmdlet to rename it from sales_report.csv to sales_report_2023.csv.

Here is the exact output in the screenshot below:

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Handle File Name Collisions

When renaming files, you may encounter a situation where a file with the new name already exists. By default, Rename-Item will throw an error in such cases. However, you can use the -Force parameter to overwrite the existing file. Here’s an example:

$oldFilePath = "C:\MyFolder\budget.csv"
$newFilePath = "C:\MyFolder\budget_2024.csv"

if (Test-Path $oldFilePath) {
    Rename-Item $oldFilePath $newFilePath -Force
    Write-Host "File renamed successfully. Existing file overwritten."
} else {
    Write-Host "The file does not exist."
}

In this case, if a file named budget_2024.csv already exists, it will be overwritten by the renamed file.

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PowerShell Check if a File Exists and Rename it with Today’s Date

In this example, I will show you how to check if a file exists and rename the file by appending today’s date to the existing file name using PowerShell.

Here is the complete PowerShell script.

$filePath = "C:\MyFolder\report.txt"

if (Test-Path $filePath) {
    $currentDate = Get-Date -Format "yyyyMMdd"
    $fileExtension = [System.IO.Path]::GetExtension($filePath)
    $newFileName = "{0}_{1}{2}" -f [System.IO.Path]::GetFileNameWithoutExtension($filePath), $currentDate, $fileExtension
    $newFilePath = Join-Path -Path (Split-Path $filePath -Parent) -ChildPath $newFileName

    Rename-Item $filePath $newFilePath
    Write-Host "File renamed successfully to $newFileName"
} else {
    Write-Host "The file does not exist."
}

Let me explain this PowerShell script:

1. We define the $filePath variable with the path to the existing file we want to check and rename.
2. We use the Test-Path cmdlet to check if the file specified by $filePath exists.
   • If the file exists, the script enters the if block.
     • Inside the if block, we use Get-Date with the -Format parameter to get today’s date in the format “yyyyMMdd” and store it in the $currentDate variable.
     • We use [System.IO.Path]::GetExtension() to extract the file extension from the original file path and store it in the $fileExtension variable.
     • We then construct the new file name by combining the original file name (without extension), today’s date, and the file extension using the "{0}_{1}{2}" format string. The result is stored in the $newFileName variable.
     • We use Join-Path to combine the parent directory of the original file path (obtained using Split-Path) with the new file name to create the complete new file path. The result is stored in the $newFilePath variable.
     • We use the Rename-Item cmdlet to rename the file from $filePath to $newFilePath.
     • Finally, we use Write-Host to display a success message indicating that the file was renamed, including the new file name.
   • If the file does not exist, the script enters the else block.
     • Inside the else block, we use Write-Host to display a message indicating that the file does not exist.

This script dynamically renames the existing file by appending today’s date to the original file name. For example, if the original file name is “report.txt” and today’s date is June 12, 2024, the renamed file will be “report_20240612.txt”.

Here is the exact output in the screenshot below:

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Example

Let me share a real-world example from my experience. I was working on a project for a client in Chicago where I needed to process a large number of CSV files daily. The files followed a specific naming convention, such as sales_data_YYYYMMDD.csv. My task was to check if the files existed and rename them to include the store location, like sales_data_YYYYMMDD_chicago.csv.

Here’s the PowerShell script I used to accomplish this:

$sourceFolder = "C:\Data\SalesReports"
$destinationFolder = "C:\Data\ProcessedReports"
$storeLocation = "chicago"

$files = Get-ChildItem $sourceFolder -Filter "sales_data_*.csv"

foreach ($file in $files) {
    $oldFilePath = Join-Path $sourceFolder $file.Name
    $newFileName = $file.BaseName + "_" + $storeLocation + $file.Extension
    $newFilePath = Join-Path $destinationFolder $newFileName

    if (Test-Path $oldFilePath) {
        Rename-Item $oldFilePath $newFilePath
        Write-Host "File $($file.Name) renamed to $newFileName"
    } else {
        Write-Host "File $($file.Name) does not exist."
    }
}

In this script, we:

1. Define the source and destination folders and the store location.
2. Use Get-ChildItem to retrieve all CSV files matching the pattern sales_data_*.csv in the source folder.
3. Loop through each file and construct the old and new file paths.
4. Check if the file exists using Test-Path.
5. If the file exists, rename it using Rename-Item and move it to the destination folder.

Conclusion

In this tutorial, I explained various methods to check if a file exists using PowerShell, such as Test-Path and Get-Item. We also learned how to rename files using the Rename-Item cmdlet and handle file name collisions with the -Force parameter. Here, I explained how to check if a file exists and rename it using PowerShell.

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