Converting Unix time to date time in powershell

Question

How would I convert a log of high precision unix format timestamps going as far as nanoseconds like in example below to date time format so to understand the timeline for these logs? Ideally if it's converted down to microsecond so can be easier correlated with events coming from Event Monitor.

16469606540.730687318: some text...
16469606541.730687318: some text...
16469606543.730687318: some text...

Answer 1

Hi @Hi @YaroC ,

something like this?

$unixTimeStamp = "1646866800.730687318"  
$date1=(Get-Date 01.01.1970)+([System.TimeSpan]::fromseconds($unixTimeStamp))  
$date1.ToString("yyyy-MM-dd HH:mm:ss.ffffff")  
  
$date2 = (Get-Date 01.01.1970).AddSeconds($unixTimeStamp)  
($date2).ToString("yyyy-MM-dd HH:mm:ss.ffffff")  

Answer 2

Hi @YaroC ,

maybe this helps?

$unixTimeStamp = "1646866800.730687318"  
$date1=(Get-Date 01.01.1970)+([System.TimeSpan]::fromseconds($unixTimeStamp))  
$date1  
  
$date2 = (Get-Date 01.01.1970).AddSeconds($unixTimeStamp)  
$date2  

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(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)

Regards
Andreas Baumgarten

Answer 3

Thanks AndreasBaumgarten. So this takes only the first part of the timestamp and gives accuracy up to seconds which isn't sufficient for my case. Would you know how to convert this further down to at least milliseconds?

Answer 4

Hey YaroC-2432,

how about using this one, the function seems to do the exact same job, I have just tested it:

From:
Convert Unix Millisecond Time In Powershell To Troubleshoot With Process Monitor
https://pavolkutaj.medium.com/convert-unix-millisecond-time-in-powershell-to-troubleshoot-with-process-monitor-435400d83436

$UnixTimeStamp = "1646866800.730687318"

function getMillis {
    param (
        $unixTimeStamp
    )
    $epochStart = Get-Date 01.01.1970 
    $millisStamp = ($epochStart + ([System.TimeSpan]::frommilliseconds($unixTimeStamp))).ToLocalTime()
    $millisStampOutput = $millisStamp.ToString("yyyy-MM-dd HH:mm:ss.ffffff")
    $millisStampClipboard = $millisStamp.ToString("HH:mm:ss.ffffff") 
    Write-Host "~~~~~~~~~~~~~~~~~~~~~~~~~~~~"
    Write-Host "Datetime: $millisStampOutput" -ForegroundColor Cyan
    Write-Host "Clipping: $millisStampClipboard" -ForegroundColor Cyan
    Write-Host "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"    
    $millisStampClipboard = $millisStamp.ToString("HH:mm:ss.ffffff") | clip
}

getMillis $UnixTimeStamp

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(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)

Regards
Stoyan Chalakov