Copy files modified in the last X days with Powershell

A friend asked on the weekend for some powershell that would allow him to copy files modified in the last 7 days to a new machine. It's a great opportunity to showcase the powershell pipeline feature!

get-childitem "c:\Source" | where-object {$_.LastWriteTime -gt (get-date).AddDays(-7)} | Copy-Item -destination "C:\Target"

This one liner will work for files in a folder (it'll get messy if we recurse though, there's a fix for that coming later).

See the pipe command '|' this used to pass the output of one command as input to another command.

1. So we get-childitem (which is the powershell name for DIR) 
2. then we pass that to where-object with a bit of code that looks at the creationtime property. the little $_. refers to the "next object in the pipeline" so we can hook into the properties of all the obejcts we found with get-childitem, perform an evaluation on the creation time,
3. Then the object is passed to copy-item

Now if we want to be able to recursively do this we'll need to be a little more tricksy!

001 002 003 004 005 006 007 008 009 010 011 012 013 014 015

$source = "c:\users\benh\documents" $target = "c:\test" $files = get-childitem $source -Recurse foreach ($file in $files) {     if ($file.LastWriteTime -ge (get-date).AddDays(-7))     {         $targetFile = $target + $file.FullName.SubString($source.Length)         New-Item -ItemType File -Path $targetFile -Force         Copy-Item $file.FullName -destination $targetFile     } }

This process uses a foreach loop which is similar to the pipeline in that it'll iterate through each item. But it allows us to use a complete script block which gives us a bit more power at the cost of performance. The main difference here is;

1. We use an IF statement to evaluate how old the file is
2. We figure out what the target path should be by dropping the $source directory from the files full name
3. We create a new-item with the path we've established
4. Then it's just copying the item as normal

Feel free to add and comments or if you've got a more elegant way of solving this problem let us know!

Reference - http://stackoverflow.com/questions/5432290/how-to-use-powershell-copy-item-and-keep-structure thanks to sentient for the recursive logic.