Using PowerShell to check a folder copied
I’ve had a number of times over the years where I’ve needed to guarantee to someone that their data is unchanged as a result of an IT action
- when we’ve migrated servers, replaced disks etc. The detailed, in depth, article by Jeff Hicks over at Petri.com “Hashing it Out in PowerShell: Using Get-FileHash” showed me that a file-hash comparison was possible in Windows without a third party piece of software.
So, inspired by that, here’s a short bit of PowerShell script to check two folders are the same- the folder had been previously copied with a
ROBOCOPY /MIR command. The script makes two lists of hashes, one for each folder, and compares the two.
1$SourceHash = Get-ChildItem -recurse X:\Folder\ | Get-FileHash 2$TargetHash = Get-ChildItem -recurse Y:\Folder\ | Get-FileHash 3Compare-Object $SourceHash.Hash $TargetHash.Hash
Or if you want to squish it to one line
1Compare-Object (Get-ChildItem -recurse X:\Folder\ | Get-FileHash).Hash (Get-ChildItem -recurse Y:\Folder\ | Get-FileHash).Hash
If the two folders are the same (i.e. the Robocopy worked as it should) then no output is displayed. To check it’s working, adding -includeequal to the end of the Compare-Object line will also output a line for identical files. For example
1Compare-Object (Get-ChildItem -recurse X:\Folder\ | Get-FileHash).Hash (Get-ChildItem -recurse Y:\Folder\ | Get-FileHash).Hash -includeequal