Add +1 every time a program has run? [duplicate] - powershell

Question

This question already has answers here:
Determine and Grab a Number Within Directory Name and Use That Number In an Expression
(2 answers)
Closed 1 year ago.
I recently wanted to improve my code by cleaning it up a bit. In my simple copy and paste program, I want to create a log file every time after the program ran. The problem is with naming the text file: I don’t want to overwrite any log-files and therefore give the file a unique name. Right now it looks like this:
start-transcript - Path $Sourcefolder\log-$logname_$logH.$logM.$logS
Basically it creates a log file based on the time you ran the program and a unique name will be given (I had to use hours, minutes and seconds in a seperate function otherwise special characters would be used but that’s not the problem)
The result would look like this:
log-08.11.202114.47.56
Not really that great.
My solution to the problem would be adding the variable $i and adding +1 every time the program run.
But if I try to do so, the value will automatically reset to 0 after it’s done.
My question, is there a way to implement this or is there another way?
(Sorry if bad format, currently on mobile)

Answer 1

Why not put an ISO8601-like timestamp in the log filename. Is granularity greater than one (1) second needed?
PS C:\> $LogFilename = 'log-' + (Get-Date -Format 'yyyyMMddTHHmmss') + '.log'
PS C:\> $LogFilename
log-20211108T083105.log

Answer 2

You could also use below reusable helper function to always ensure a unique filename:
function Get-UniqueFileName {
[CmdletBinding()]
Param(
[Parameter(ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true, Mandatory = $true, Position = 0)]
[Alias('FullName')]
[string]$Path # the suggested full path and filename
)
$directory = [System.IO.Path]::GetDirectoryName($Path)
$baseName = [System.IO.Path]::GetFileNameWithoutExtension($Path)
$extension = [System.IO.Path]::GetExtension($Path) # this includes the dot
# get an array of all files with the same extension currently in the directory
$allFiles = #(Get-ChildItem $directory -File -Filter "$baseName*$extension" | Select-Object -ExpandProperty Name)
# construct the possible new file name (just the name, not the full path and name)
$newFile = $baseName + $extension
$seed = 1
while ($allFiles -contains $newFile) {
# add the seed value between brackets. (you can ofcourse leave them out if you like)
$newFile = "{0}({1}){2}" -f $baseName, $seed, $extension
$seed++
}
# return the full path and filename
return Join-Path -Path $directory -ChildPath $newFile
}
In your case you can then do:
$Sourcefolder = 'D:\Test'
$logFile = Join-Path -Path $Sourcefolder -ChildPath ('{0:yyyyMMdd}.log' -f (Get-Date)) | Get-UniqueFileName
Example:
If a file called D:\Test\20211108.log already exists in your source folder, this will return a new filename D:\Test\20211108(1).log. The next one will be D:\Test\20211108(2).log etc.
or, as already commented, you can use the DateTime Ticks property te be pretty sure the filename will be unique:
$logFile = Join-Path -Path $Sourcefolder -ChildPath ('{0}.log' -f (Get-Date).Ticks)
Returns D:\Test\637719832681865978.log