Import Bulk Users to Active Directory

1) Build CSV file that include Organization Users with specific attributes to be imported in the new Windows 2008 R2 Active Directory,
Sample of CSV can be as the following:
Recommendation
For simplicity’s sake we’ll keep it to a few basic properties like Name and Description, of course Organization IT team can and normally would have significantly more. To make it easier IT team can add a few extra columns like the SamAccountName and the Path (OU) where Organization would like the account to be created, and for account password IT team can configure random or fixed password for all users and force it for all users and distribute the new passwords for each user individually while configure all users to be forced to change password after first login.
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2) Use cmdlet Import-CSV which read from a standard CSV file and create a set of objects based on data inside the CSV file, then send the results of this cmdlet using PowerShell pipeline to New-ADUser cmdlet from ActiveDirectory module to create the specified users in the Active Directory, as a sample cmdlet: “Import-CSV C:\Users.csv | New-ADUser” this command to be run from Active Directory PowerShell Module.
3) Verify that the users in CSV are imported in the Active Directory.

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Courtesy:http://blogs.technet.com/b/bettertogether/archive/2011/01/09/import-bulk-users-to-active-directory.aspx