I'm trying to create a DateTime object with a specific UTC timestamp in PowerShell. What's the simplest way to do this?
I tried:
Get-Date
-Format (Get-Culture).DateTimeFormat.UniversalSortableDateTimePattern
-Date "1970-01-01 00:00:00Z"
but I get this output:
1969-12-31 19:00:00Z
It's a few hours off. Where's my lapse in understanding?
The DateTime object itself is being created with the proper UTC time. But when PowerShell prints it out it converts it to my local culture and time zone, thus the difference.
Proof:
$UtcTime = Get-Date -Date "1970-01-01 00:00:00Z"
$UtcTime.ToUniversalTime()
Get-Date converts the given UTC time to local time and stores it as a datetime object with Kind set to Local. It does store the correct physical point in time, but it is a local time and will be printed in local time. Note that this still IS a correct answer to the question. OP did not specifically ask for creating a datetime object with kind UTC. Upvoted.
(get-date).ToUniversalTime().ToString("yyyyMMddTHHmmssfffffffZ")
.ToString("yyyyMMddTHHmmssfffffffZ") eg. 02:00:00PM should become ..140000 since UTC is timezone-agnostic
PowerShell -NoProfile -ExecutionPolicy Bypass -Command "((get-date).ToUniversalTime()).ToString(\"yyyy-MM-ddTHH:mm:ss+0000\")"
$utctime = New-Object DateTime 1970, 1, 1, 0, 0, 0, ([DateTimeKind]::Utc)
If you print out $utctime, then you get:
1. januar 1970 00:00:00
Also, $utctime.Kind is correctly set to Utc.
$time = [DateTime]::UtcNow | get-date -Format "yyyy-MM-ddTHH:mm:ssZ"
This appears to also work
[DateTime]::UtcNow.ToString('u') is a better choice as those MM and mm might be misspelled. I filed such a bug in a system the other month.You can use the SpecifyKind method:
PS C:\IT\s3> $timestamp
Wednesday, July 18, 2018 7:57:14 PM
PS C:\IT\s3> $timestamp.kind
Unspecified
PS C:\IT\s3> $utctimestamp = [DateTime]::SpecifyKind($timestamp,[DateTimeKind]::Utc)
PS C:\IT\s3> $utctimestamp
Wednesday, July 18, 2018 7:57:14 PM
PS C:\IT\s3> $utctimestamp.kind
Utc
This is how it works in .NET, right? PowerShell just calls the ToUniversalTime method. From http://msdn.microsoft.com/en-us/library/system.datetime.touniversaltime.aspx
The Coordinated Universal Time (UTC) is equal to the local time minus the
UTC offset. For more information about the UTC offset, see TimeZone.GetUtcOffset.
The conversion also takes into account the daylight saving time rule that applies
to the time represented by the current DateTime object.
In Powershell, the method
New-Object DateTime(9999, 12, 31, 23, 59, 59, 59, ([DateTimeKind]::Utc))
is the correct one, as the others create the time in Local TZ, and then convert it and store it in UTC and then it can be displayed again in UTC, whereas the above method creates it in UTC in the first place.
You can test this by reaching the .NET DateTime limits like the above, whereas if you run the script from the "accepted solution" at the limits
(Get-Date -Date "9999-12-31T23:59:59.99Z").ToUniversalTime()
run from a system with a local time zone ahead of UTC, e.g. UTC+1, then you'll receive the below error:
Get-Date: Cannot bind parameter 'Date'. Cannot convert value "9999-12-31T23:59:59.99Z" to type "System.DateTime". Error: "The DateTime represented by the string '9999-12-31T23:59:59.99Z' is out of range."
