How to Get a File Name Without the Extension in PowerShell

Why Get the File Name Without the Extension?

Here are some of the most common use cases:

• Iterate files in a folder – When processing files in a directory, you often need to act on the file name rather than the full name with an extension. Looping through the base names allows easier grouping, sorting, and logic.
• Construct new file paths – Dynamically building file paths is easier when appending a new extension to the base file name. This avoids retaining the old file type.
• Validate names – Removing the extension lets you validate that file names meet given naming policies. The base name is what gets exposed to users.
• Standardization – Eliminating extensions can help standardize file names for easier processing and identification. The variance in extensions may not always provide value.
• Display purposes – Displaying file names without extensions focuses attention on the meaningful descriptive part rather than the file type technical details.

These kinds of use cases require reliably grabbing file names minus that trailing dot extension. Let’s explore how to do just that in PowerShell.

Core Methods to Get File Names Without Extension

PowerShell offers several approaches to get a file name without the extension. Let’s break down the core methods available:

Split the Base and Extension with Split-Path

The Split-Path cmdlet has a parameter -LeafBase that splits the file into the base name and extension portions. Here is an example:

$filePath = './documents/my-file.docx'
$baseName = Split-Path $filePath -LeafBase

# Result: my-file

This neatly separates the two pieces by file path. The key things to know about -LeafBase:

• Outputs the base name string directly
• Returns $null if no directory separators present
• Doesn’t work directly on file name strings

So while handy on file paths, it may not suffice when dealing with plain file names already extracted from directories.

Remove Extension via Substring Index

Another way is locating the last period in the file name to isolate the extension substring:

$fileName = 'my-file.docx'
$nameOnly = $fileName.Substring(0, $fileName.LastIndexOf('.'))

# Result: my-file

The key aspects when using substring index to remove extensions:

• Specify 0 index to start from beginning
• Call LastIndexOf() method to locate final period
• Works on any file name string, with or without path

This gives you flexibility for any string input, but requires a bit more logic to find the extension splitting point.

Cut Off Extension Via Regex Match

PowerShell’s regex abilities give another option – use a regular expression to match and remove the file extension:

$fileName = 'my-file.docx' 
$nameOnly = $fileName -replace '\.[^.]*$', ''

# Result: my-file

Here’s what the regex does:

• Matches dot followed by any characters up to the end
• Removes the entire matched portion
• Leaves only the base file name

Regex provides tons of flexibility for complex file naming scenarios. But for a simple extension removal, it may be more overhead than needed.

Split FileName with Split() Method

The .Split() method on strings can divide a file name based on a character separator.

$fileName = 'my-file.docx'
$nameParts = $fileName.Split('.')
$baseName = $nameParts[0]  

# Result: my-file

Key aspects when splitting on file extensions:

• Split on . period to separate into parts
• Grab first array element [0] to get base name portion
• Straightforward approach when dealing with plain strings

This leverages the file naming convention of delimiting with periods. As long as your filename contains a dot extension, splitting on the period nicely divides out the base name.

Those are some of the core methods to remove the extension from a file name in PowerShell. But which approach is best? Let’s explore some key nuances.

Comparing Core Approaches to Remove File Extensions

While each of those core methods works, they have some notable differences to consider:

1. String Type Requirements

• Split-Path -LeafBase requires a file path
• Other methods work on plain file name strings

This means if starting without a file path, Split-Path won’t suffice.

2. Substring Logic to Find Extension Index

• Substring index requires extra logic to find last period
• Regex and Split approaches handle match internally

Having to find the dot before removing extension chars adds extra work compared to the other methods.

3. Performance Speed

• Split-Path cmdlet slower than string methods
• Substring fastest since acts directly on string

For raw speed, stick with the Substring, Split(), or Replace options over calling the external command.

4. Readability of Logic

• Substring easiest to grasp logic
• Regex more complex to decipher

If aiming for clean, readable code, Substring tends to be cleaner than the regex approach.

5. Flexibility for Complex Strings

• Regex shines for convoluted naming and globs
• Split() good for consistent delimiter like dot

When dealing with consistent file extensions delimited by a dot, Split() on the dot handles even complex base names well.

So in summary:

• If starting with file path already – -LeafBase works great
• If no file path given – stick to string methods
• Substring simplest logic when no globs/wildcards
• Prefer Split() over Replace() regex for readability
• Regex most flexible for irregular naming patterns

With those key considerations in mind, let’s see some examples applying these techniques in real world scenarios.

Practical Examples Removing File Extension

Let’s walk through some applied examples of getting the file name without extension in PowerShell using the various approaches:

Iterating Files in Directory

Say we need to iterate through files in a directory, grouping names by type while ignoring file extensions. The -LeafBase parameter handles this case easily:

$files = Get-ChildItem C:\Documents\*

$typeGroups = @{}

foreach ($file in $files) {

  $name = Split-Path $file.FullName -LeafBase  

  if (-not $typeGroups.ContainsKey($name)) {
    $typeGroups.Add($name, @())
  }

  $typeGroups[$name] += $file.Name
}

$typeGroups

By extracting the base name via -LeafBase at each iteration, we can group on the name while omitting the varying extensions per file.

Constructing New File Path

When programmatically constructing new file paths, retaining only the base name allows seamlessly appending an new extension:

$fileName = 'my-file.docx'

$base = $fileName.Substring(0, $fileName.LastIndexOf('.'))
# Base name: my-file

$newName = $base + '.txt' 
# New name: my-file.txt

$newPath = Join-Path C:\Documents $newName
# Path + name: C:\Documents\my-file.txt

By stripping the .docx first, we get a clean base file name to then add the desired .txt extension later.

Standardize Display Names

To display files names without extensions, we can clean the names by removing dots and chars that follow:

Get-ChildItem .\Reports | Foreach-Object { 

  $name = $_.Name.Split('.')[0]

  [PSCustomObject]@{
    CleanName = $name 
    Path = $_.FullName
  }

} | Format-Table CleanName, Path

Here we standardize displaying only the base portion for easier visual recognition, while still retaining the full path value behind the scenes.

The use cases are endless, but separating base file name from extension first opens up all kinds of opportunities.

Now that we’ve covered why, how, and real-world examples, let’s call out some best practices when implementing your own extension removal logic.

Best Practices Getting Base File Name

Getting base name Here are some best practices when getting the file name without extension in PowerShell:

Validate Extension Exists

Before removing an extension, first check the file name contains one:

$fileName = 'myfile'

if ($fileName -notlike '*.*') {
  # No extension present
  return  
}

$baseName = $fileName.Split('.')[0]

This avoids errors trying to split or remove non-existent extensions.

Handle No Extension Gracefully

Speaking of, handle cases where no extension exists without throwing errors:

$baseName = $fileName

if ($fileName -like '*.*') {
  $baseName = $fileName.Substring(0, $fileName.LastIndexOf('.'))
}

# $baseName contains clean name

Now extensionless names won’t break the logic.

Use Splatting for Readability

Splatting parameters for cmdlets like Split-Path improves readability:

$param = @{
  Path = $fileName 
  LeafBase = $true
}

$baseName = Split-Path @param

This avoids convoluted parameter strings.

Watch for Unexpected File Types

Unexpected double extensions like .config.xml can trip up extension stripping logic. Plan for odd cases by handling or validating against complex naming schemes.

Keep Original File Name Too

Maintain the original name somewhere in case needed later:

$original = $fileName
$baseName = $fileName.Split('.')[0]

This ensures you can reconstruct the fully qualified name if required.

Comment Code

Use comments to explain the intention behind multi-line file name manipulation logic:

# Split file name on dot delimiter to remove extension
$nameParts = $fileName.Split('.') 

# Keep only base name portion
$baseName = $nameParts[0]

Clear annotations prevent future confusion.

Validate Results

Double check results look as expected, at least for initial runs or testing:

$base = Get-BaseName $fileName

if ($base -ne ‘mybase’) {
  Write-Error “Base name incorrect!”
}

This catches any missed logic errors early.

Keeping these best practices in mind will help tame even the most complex file renaming operations.

Removing that pesky file extension opens up all kinds of opportunities. Give one of these PowerShell options a try in your own extension-removal challenges!