Convert date to unixt timestamp - powershell

Question

I need your help

I have output from csv file which look like below, and I need to convert dates into Unix timestamp. Header "Scheduled Start Date Time" can be removed by simple replace command in order to keep only dates, however each row need to be changed into UNIX timestamp.

Scheduled Start Date Time
2020-04-14 19:00
2020-04-15 06:00
2020-04-15 06:00
2020-04-15 14:00
2020-04-15 14:00
2020-04-15 09:00
2020-04-15 14:00
2020-04-15 09:00

I tried something like that, but it is not working:

$trimfile = Get-Content -Path "C:\Users\timestamp.txt"
Get-Date -Date $trimfile -UFormat %s | Out-File "C:\Users\timestamp1.txt"

Answer 1

Unix epoch starts at Jan 1 1970, so just subtract that date from your current date and count the number of seconds in between:

# Read all timestamps into variable
$timestamps = Get-Content C:\Users\timestamp.txt |Select -Skip 1

# Define unix epoch
$unixEpoch  = Get-Date '1970-01-01'

# Loop over all timestamps
for($i = 1; $i -le $timestamps.Count; $i++){
  # Calculate UTC corresponding to the timestamp
  $currentUtc = (Get-Date $timestamps[$i-1]).ToUniversalTime()

  # Calculate + round total number of seconds since epoch
  $totalSeconds = ($currentUtc - $unixEpoch).TotalSeconds
  [Math]::Round($totalSeconds) |Out-File "C:\Users\timestamp${i}.txt"
}

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If the locale on the machine doesn't recognize the timestamp format, use [datetime]::Parse($timestamp[$i-1], [cultureinfo]::InvariantCulture) instead of Get-Date $timestamp[$i-1]