(PowerShell) Set a Custom Last-Modified Date in a Gzip File

See more Gzip Examples

This example demonstrates how to use the SetDt method to specify a custom last-modified date and time that will be embedded in a Gzip file.

A CkDateTime object is first initialized with a specific date/time using an RFC 822 formatted string. This date/time is then applied to the Gzip object using SetDt.

When a compression method is called (such as CompressStringToFile), the specified date/time is included in the Gzip metadata. This allows the resulting .gz file to carry a meaningful timestamp rather than using the current system time.

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

$success = $false

# This example demonstrates how to set a custom last-modified date/time
# that will be embedded in a Gzip file.

$gzip = New-Object Chilkat.Gzip
$dt = New-Object Chilkat.CkDateTime

# Set the date/time using a timestamp format (ISO 8601 style):
$dt.SetFromTimestamp("2025-11-15T12:45:26-05:00")

# Apply the date/time to the Gzip object:
$success = $gzip.SetDt($dt)
if ($success -eq $false) {
    $($gzip.LastErrorText)
    exit
}

# Compress a string so the custom date/time is embedded in the .gz:
$inputStr = "Example text for Gzip compression."
$success = $gzip.CompressStringToFile($inputStr,"utf-8","output.gz")
if ($success -eq $false) {
    $($gzip.LastErrorText)
    exit
}

$("Gzip file created with custom last-modified date.")