Whenever you change a file, the file system automatically updates the LastWriteTime property. If you'd like to change a file without leaving such traces, try this:
# make sure this file and folder exist!! $path = 'c:\temp\somefile.txt' $file = Get-Item $Path $lastModified = $file.LastWriteTime # change file content: "More Stuff" >> $Path # replace modification date: $file.LastWriteTime = $lastModified
As you can see, Get-Item returns a file object that gives you easy read/write access to file information such as LastWriteTime, CreationTime, or LastAccessTime. After the file is changed, the information is simply restored, and the updated file receives the old modification timestamp.