Formatting Dates in PowerShell - powershell

I am currently trying to convert a date from the one displayed in regedit to a readable datetime format. But I do not know how to do this, I'm working with the following:
.GetValue('InstallDate')
And in the .csv file, it display it as this: 20150914
How would I go about converting that into a readable date?

try
[datetime]::Parseexact("20150914","yyyyMMdd", $null )

I'm not sure why you down voted the other answer because he is right on the money with [Datetime]::ParseExact you will have to deal with the null values though
$Regbase = Get-ChildItem HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\
foreach ($entry in $regBase)
{
$date = (Get-ItemProperty HKLM:\$entry | select installdate).installdate
try
{
[DateTime]::ParseExact($date, "yyyyMMdd", [CultureInfo]::InvariantCulture)
}
catch [exception]
{
"Date Value: $date"
}
}

PowerShell Date is just .NET DateTime. Check DateTime.ParseExact.
[DateTime]::ParseExact("20151010", "yyyyMMdd", [CultureInfo]::InvariantCulture)

Related

How do I use "DO... Until" for a script date prompt

I am trying to use "DO...Until" in a script to require a user to enter a date. I want to ensure that the date is valid and that the script is able to use that date. I'm fairly new to PS and I'm not certain what I'm doing wrong. It keeps looping even if I put in a valid date.
Do #Start Get Effective Date#
{
$StartDate = Read-Host ' What is the effective date? Format: MM/DD/YYYY '
if ($StartDate -ge 1)
{ Write-Host " You Entered an Effective date of: $StartDate "
}
else
{ Write-Host " Please enter the effective date " -ForegroundColor:Green }
} Until ($StartDate -ge 1)
#End Get Effective Date#
I'm not certain if I am using the wrong '-ge' or not. Once I am able to get a valid date from the user I want the script to move to the next step.
you were close to ;-)
Do{
[string]$StartDate = Read-Host 'What is the effective date? Format: MM/DD/YYYY'
try {
[datetime]$StartDate = [datetime]::ParseExact($startdate, 'MM/dd/yyyy', [cultureinfo]::InvariantCulture)
}
Catch {
}
}
Until ($StartDate -is [DateTime])
The TryParseExact method seems a good fit for what you're looking to achieve, no need for error handling:
[ref] $date = [datetime]::new(0)
do {
$startdate = Read-Host 'What is the effective date? Format: MM/DD/YYYY'
$parsed = [datetime]::TryParseExact($startdate, 'MM/dd/yyyy', [cultureinfo]::InvariantCulture, [Globalization.DateTimeStyles]::None, $date)
} until($parsed)
$date.Value
To offer a concise alternative that relies on the fact that casting a string to [datetime] in PowerShell by default recognizes date strings such as '12/24/2022' (representing 24 December 2022), irrespective of the current culture, because PowerShell's casts, among other contexts, use the invariant culture:
$prompt = 'What is the effective date? Format: MM/DD/YYYY'
# Keep prompting until a valid date is entered.
while (-not ($startDate = try { [datetime] (Read-Host $prompt) } catch {})) {}
"Date entered: "; $startDate
Note: A [datetime] cast also recognizes other string formats, such as '2022-12-24'
Another option would be to create a PowerShell function and accept the date as a parameter. Functions can use a variety of approaches for parameter validation, including script.
https://learn.microsoft.com/powershell/module/microsoft.powershell.core/about/about_functions_advanced_parameters?view=powershell-7.2

compare line to string variable in powershell

I have txt file with date value, line by line
I try to compare them to today date in powershell but its not working
$DateTimeNow = (Get-Date).ToString('dd/MM/yyyy')
$data2 = get-content "output.txt"
$z= #()
foreach($line2 in $data2)
{
if($line2 -match $DateTimeNow){
write-host "same date"
}
}
the compare with "match" not work, I have try -eq and = but nothing better.
Have you any idea what I am doing wrong ?
The input dates all use 2-digit notation for the year (20 for 2020), but your string representing today's date uses 4-digits. Change to the appropriate format and it will work:
$DateTimeNow = Get-Date -Format 'dd/MM/yy'

PowerShell Comparing Date issue

I created a small scrip that have do to a couple of thinks.
get string from description field from user in specific container
take part of this string (substring method) that holds date information
convert this string to date format
compare this formated string with a current date - 30 days and do sth
The problem is that comparing is not working correctly. I tried do recognise date that is older than 30 days and do something but i see that comparison not always work. sometimes it does not recognize that date is less then - 30 days from current day
Script below
$DateMaxTime = (Get-date).AddDays(-30)
$DateFormatMaxTime = Get-Date $DateMaxTime -Format dd/MM/yyyy
$getData = get-ADUser -Filter * -Properties * -SearchBase "OU=Disabled,OU=Control,OU=x,OU=x,DC=x,DC=x,DC=x" `
|where {$_.Description -like "LEFT*"} |select name,samaccountname,description
Foreach ($Data IN $getData){
$DataPart = $null
$DataPart=$Data.description
$DatePart= $DataPart.substring(5,10)
$FinalDate = [datetime]::ParseExact($DatePart,'dd/MM/yyyy',$null)
$FinalDateFormat = Get-Date $FinalDate -Format dd/MM/yyyy
If ($FinalDateFormat -lt $DateFormatMaxTime ){ Write-Host "$($Data.samaccountname), $($Data.description) moved to deleteMe" }
else{ Write-Host "$($Data.samaccountname), $($Data.description) still in disabled" }
}
Below output shows me the wrong results (as example i did it for one user - >
Based on this logic the value $FinalDateFormat that hold date -> 31-12-2018 is less then value $DateFormatMaxTime that hold this date -> 25-06-2019 but it still applies else statement ...
I am not sure why, i did something wrong with date conversion ?
I put the comments as the answer:
I would compare the datetime versions of the dates rather than the string versions.
If ($FinalDate -lt $DateMaxTime)
Running
get-date -format
makes them strings.
$finaldate.gettype(); $datemaxtime.gettype()
shows the types. They are [datetime], not [string] like the other two.

Compare dates from a string in PowerShell [duplicate]

This question already has answers here:
Compare Get-Date to Date as String
(1 answer)
How to parse (French) full month into datetime object in PowerShell?
(1 answer)
Closed 4 years ago.
$Deldate = "19-06-2018"
$Newdate = "04-06-2018"
I need to check which date is bigger.
if ($Deldate -ge $NewDate) {
write-host "NewDate is bigger"
}
else {
write-host "Deldate is bigger"
}
This is not working for me, and it looks like the format is not "System.DateTime". I'm getting the date values are from an external CSV file. How do I find a solution for this?
You should be able to cast the strings that you have created to the "datetime" type like so:
$Deldate = "19-06-2018"
$Newdate = "04-06-2018"
$Deldate = [datetime]::ParseExact("$Deldate", 'dd-MM-yyyy', $null)
$Newdate = [datetime]::ParseExact("$Newdate", 'dd-MM-yyyy', $null)
if ($Deldate -ge $NewDate) {
write-output "NewDate is bigger than or equal to"
}
else {
write-output "Deldate is bigger"
}
This returns the correct result. You can't simply use the Get-Date cmdlet, since the -Date required parameter also requires that the parameter be of type "DateTime", so you first have to cast the strings to the DateTime type.
Originally Proposed...
I am going to change the format of your date just a hair from DD-MM-YYYY to MM-DD-YYYY:
$Deldate = Get-Date "06-19-2018"
$Newdate = Get-Date "06-04-2018"
if ($Deldate -gt $Newdate) {
'Deldate is larger'
}
else {
'Newdate is larger or equal'
}
I'm creating two date objects based on the respective dates you gave. I'm comparing the two objects; PowerShell knows how to do the date math.
It works fine for U.S. style dates.
After much discussion...
However, for non-US style dates, consider calling datetime's constructor:
$Deldate = New-object 'datetime' -ArgumentList 2018, 6, 19, $null, $null, $null
$Newdate = New-object 'datetime' -ArgumentList 2018, 6, 4, $null, $null, $null
if ($Deldate -gt $Newdate) { 'Deldate is larger' } else { 'Newdate is larger or equal' }
Or, as proposed the [datetime]::ParseExact() method; documented here.
PowerShell is good with dates; it just has to know it's a date...
$Deldate = get-date "19-06-2018"
$Newdate = get-date "04-06-2018"
if ($Deldate -ge $NewDate) {
write-host "NewDate is bigger"
}
else {
write-host "Deldate is bigger"
}
Note: You could cast [datetime]$Deldate ="19-06-2018", but as explained in comments to PowerTip: Convert String into DateTime Object, it's valid only for US date format.

Compare Dates in loop

I have a requirement where I need to read a date from a CSV file and compare it to a date variable within the script. However, my code doesn't work when some of the date entries in the CSV file are blank. Any idea how I can store a blank date in [datetime] variable?
Here's the part of my code:
#This is my date variable in script
$InactivityDate = (Get-Date).AddDays(-62).Date
Import-Csv $MyCSV | ForEach {
#This is the date variable i'm reading from csv file
$whenCreated = $_.whenCreated
#This converts value in string variable $whenCreated to [DateTime] format
$ConvertWhenCreated = ([datetime]::ParseExact($whenCreated,"dd/MM/yyyy",$null))
#Comparing dates
if($ConvertWhenCreated -le $InactivityDate)
{
"Account is dormant"
}
Above code works fine when $whenCreated contains some value, but when it's blank PowerShell obviously cannot compare a date variable with blank value :(
The only solution I can see now is to check if $whenCreated is blank and save a very old date like it happens in Excel, e.g.:
if($whenCreated -eq "")
{
$whenCreated = "01/01/1900 00:00:00"
}
Should this be OK or is there another logical solution?
Your problem most likely isn't with the comparison, but with the conversion of the blank value to a date via ParseExact(). If you want accounts with no date treated as dormant you could simply do something like this:
$whenCreated = $_.whenCreated
if ($whenCreated) {
$whenCreated = [DateTime]::ParseExact($whenCreated, 'dd/MM/yyyy', $null)
}
if ($whenCreated -le $InactivityDate) {
'Account is dormant'
}
Checking if an empty string (or $null) is lesser or equal to $InactivityDate will return $true as long as $InactivityDate contains a date.
You already test if the string is empty, which is good. But there is no need to assign a fake old date, you can simply assign $null:
$InactivityDate = (Get-Date).AddDays(-62)
$dateString = "2014-11-01"
if ($dateString) {
$date = Get-Date $dateString
} else {
$date = $null
}
if ($date -le $InactivityDate) {
"Account is dormant"
}