numerate new versions of a file copied into a folder - powershell

Question

I have a file that is generated daily. It is generated with the filename dailyfile.dat.
The file needs to be copied into a destination folder and numerated with a single digit that is one higher than the file already in the destination folder so that all files coexist and have no gap in numeration.
In other words, I need each day's copy to add +1 to whatever is already in the destination folder. If 0,1 & 2 exist in the destination folder, then the new copy placed in the destination should be named 3 and so on. If no files exist, it gets named 0.
i.e.
Exists
c:\source\dailyfile.dat
c:\destination\dailyfile0.dat
process
copy c:\source\dailyfile.dat -> c:\destination\dailyfile1.dat
results
c:\destination\dailyfile0.dat
c:\destination\dailyfile1.dat

Answer 1

Alternatively you could parse the name of the file, get the number off the end, select the highest number, and add one to create the new path. This has the advantage of being able to "pick up where you left off" if you ever archive some of your daily files.
$src = 'c:\source\dailyfile.dat'
$dstFolder = 'c:\destination'
[int32]$LastFile = Get-ChildItem $dstFolder |
Where {$_.BaseName -match "^dailyfile(\d+)"} |
ForEach {$Matches[1]} |
Sort -Descending |
Select -First 1
If ($LastFile) {$LastFile++} else {$LastFile = 0}
$Dest = "C:\Destination\DailyFile$LastFile.dat"
Copy-Item $src -Dest $Dest
This way if you archive them annually or something in a couple years you would end up with (assuming you always leave at least 1 file in the folder):
Mode LastWriteTime Length Name
---- ------------- ------ ----
d---- 5/21/2015 7:47 PM 2015
d---- 5/21/2016 7:47 PM 2016
-a--- 5/21/2017 2:00 PM 580984 DailyFile730.dat
-a--- 5/22/2017 2:00 PM 392610 DailyFile731.dat

Answer 2

Something like this should work:
$src = 'c:\source\dailyfile.dat'
$dstFolder = 'c:\destination'
$f = Get-Item $src
$n = 0
do {
$dst = Join-Path $dstFolder ($f.BaseName + $n + $f.Extension)
$n++
} while (Test-Path -LiteralPath $dst)
Copy-Item $src $dst

Answer 3

Adding to Ansgar's post, if you can include a separator character like _ then you could use:
$src = 'c:\source\dailyfile.dat'
$dstFolder = 'c:\destination'
#Get the number from the last file in the destination directory
[int]$NextNum = [int](gci $dstFolder | Sort-Object -Property Basename | Select -Last 1).basename.split("_")[1] + 1
#Get source file
$f = Get-Item $src
# Add more zeros in the ToString for more padding
$dst = Join-Path $dstFolder ($f.BaseName + "_" + $NextNum.ToString("000") + $f.Extension)
Copy-Item $src $dst