(PowerShell) Compress a File to Gzip with Custom Metadata

See more Gzip Examples

This example demonstrates how to use the CompressFile method to create a Gzip (.gz) file while customizing the metadata embedded in the Gzip header.

Before compression, several properties are set:

• Comment: Adds a descriptive comment to the Gzip file.
• Filename: Specifies the filename to embed in the Gzip data, which may be used by extraction tools as the default output name.
• CompressionLevel: Controls the tradeoff between compression ratio and speed (set to maximum in this example).
• LastModStr: Sets the last-modified timestamp using an RFC 822 formatted date string.

After setting these properties, the input file is compressed and written to a .gz file. This approach allows you to embed meaningful metadata along with the compressed data.

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

# This example demonstrates how to compress a file to Gzip format
# while setting custom metadata such as comment, filename,
# compression level, and last-modified date.

$gzip = New-Object Chilkat.Gzip

# Set custom Gzip properties:
$gzip.Comment = "Example Gzip file created with Chilkat"
$gzip.Filename = "custom_name.txt"
$gzip.CompressionLevel = 9
$gzip.LastModStr = "Wed, 1 Apr 2025 12:45:26 -0500"

# The file to be compressed:
$inputFile = "example.txt"
$outputFile = "example.txt.gz"

# Compress the file:
$success = $gzip.CompressFile($inputFile,$outputFile)
if ($success -eq $false) {
    $($gzip.LastErrorText)
    exit
}

$("Compression successful.")
$("Gzip file created: " + $outputFile)