Working with files and folders - PowerShell

Listing all files and folders within a folder

You can get all items directly within a folder using Get-ChildItem . Add the optional Force parameter to display hidden or system items. For example, this command displays the direct contents of PowerShell Drive C: .
Get-ChildItem -Path C:\ -Force
The command lists only the directly contained items, much like using the dir command in cmd.exe
or ls in a UNIX shell. To show items in subfolder, you need to specify the Recurse parameter.
The following command lists everything on the C: drive:
Get-ChildItem -Path C:\ -Force -Recurse
Get-ChildItem can filter items with its Path, Filter, Include, and Exclude
parameters, but those are typically based only on name. You can perform complex filtering based on
other properties of items using Where-Object.
The following command finds all executables within the Program Files folder that were last modified
after October 1, 2005 and that are neither smaller than 1 megabyte nor larger than 10 megabytes:
Get-ChildItem -Path $env:ProgramFiles -Recurse -Include *.exe |
    Where-Object -FilterScript {
        ($_.LastWriteTime -gt '2005-10-01') -and ($_.Length -ge 1mb) -and ($_.Length -le 10mb)
Copying files and folders
Copying is done with Copy-Item. The following command backs up C:\boot.ini to C:\boot.bak:
Copy-Item -Path C:\boot.ini -Destination C:\boot.bak
If the destination file already exists, the copy attempt fails. To overwrite a pre-existing
destination, use the Force parameter:
Copy-Item -Path C:\boot.ini -Destination C:\boot.bak -Force
This command works even when the destination is read-only.
Folder copying works the same way. This command copies the folder C:\temp\test1 to the new folder
C:\temp\DeleteMe recursively:
Copy-Item C:\temp\test1 -Recurse C:\temp\DeleteMe
You can also copy a selection of items. The following command copies all .txt files contained
anywhere in C:\data to C:\temp\text:
Copy-Item -Filter *.txt -Path c:\data -Recurse -Destination C:\temp\text
You can still use other tools to perform file system copies. XCOPY, ROBOCOPY, and COM objects, such
as the Scripting.FileSystemObject, all work in PowerShell. For example, you can use the Windows
Script Host Scripting.FileSystem COM class to back up C:\boot.ini to C:\boot.bak:
(New-Object -ComObject Scripting.FileSystemObject).CopyFile('C:\boot.ini', 'C:\boot.bak')
Creating files and folders
Creating new items works the same on all PowerShell providers. If a PowerShell provider has more
than one type of item—for example, the FileSystem PowerShell provider distinguishes between
directories and files—you need to specify the item type.
This command creates a new folder C:\temp\New Folder:
New-Item -Path 'C:\temp\New Folder' -ItemType Directory
This command creates a new empty file C:\temp\New Folder\file.txt
New-Item -Path 'C:\temp\New Folder\file.txt' -ItemType File
Important
When using the Force switch with the New-Item command to create a folder, and the folder
already exists, it won't overwrite or replace the folder. It will simply return the existing
folder object. However, if you use New-Item -Force on a file that already exists, the file
is overwritten.
Removing all files and folders within a folder
You can remove contained items using Remove-Item, but you will be prompted to confirm the
removal if the item contains anything else. For example, if you attempt to delete the folder
C:\temp\DeleteMe that contains other items, PowerShell prompts you for confirmation before
deleting the folder:
Remove-Item -Path C:\temp\DeleteMe
Confirm
The item at C:\temp\DeleteMe has children and the Recurse parameter wasn't
specified. If you continue, all children will be removed with the item. Are you
sure you want to continue?
[Y] Yes  [A] Yes to All  [N] No  [L] No to All  [S] Suspend  [?] Help
(default is "Y"):
If you don't want to be prompted for each contained item, specify the Recurse parameter:
Remove-Item -Path C:\temp\DeleteMe -Recurse
Mapping a local folder as a drive
You can also map a local folder, using the New-PSDrive command. The following command creates a
local drive P: rooted in the local Program Files directory, visible only from the PowerShell
session:
New-PSDrive -Name P -Root $env:ProgramFiles -PSProvider FileSystem
Just as with network drives, drives mapped within PowerShell are immediately visible to the
PowerShell shell. To create a mapped drive visible from File Explorer, use the Persist
parameter. However, only remote paths can be used with Persist.
Reading a text file into an array
One of the more common storage formats for text data is in a file with separate lines treated as
distinct data elements. The Get-Content cmdlet can be used to read an entire file in one step,
as shown here:
PS> Get-Content -Path C:\boot.ini
[boot loader]
timeout=5
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional"
 /noexecute=AlwaysOff /fastdetect
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS=" Microsoft Windows XP Professional
with Data Execution Prevention" /noexecute=optin /fastdetect
Get-Content treats the data read from the file as an array, with one element per line of file
content. You can confirm this by checking the Length of the returned content:
PS> (Get-Content -Path C:\boot.ini).Length
This command is most useful for getting lists of information into PowerShell. For example, you might
store a list of computer names or IP addresses in the file C:\temp\domainMembers.txt, with one
name on each line of the file. You can use Get-Content to retrieve the file contents and put them
in the variable $Computers:
$Computers = Get-Content -Path C:\temp\DomainMembers.txt
$Computers is now an array containing a computer name in each element.