UPDATE: The script now supports uploading files larger than 2MB.

Another PowerShell sample script for you. This one uploads all files within a specified local directory to a Document Library within a Site in an O365 tenant.

All you need to run this script is an O365 tenant, the SharePoint client components SDK installed on the machine running the script - http://www.microsoft.com/en-us/download/details.aspx?id=35585 and to update the $User, $SiteURL, $DocLibName (name of the destination Document library) and $Folder (path to the local folder containing the files to upload) variables. When the script is executed it will prompt for the password of the user specific in the $User variable.

One thing to point out is that CSOM has a maximum upload size of 2MB.

#Specify tenant admin and site URL
$User = "admin@tenant.onmicrosoft.com"
$SiteURL = "https://tenant.sharepoint.com/sites/site"
$Folder = "C:\FilesToUpload"
$DocLibName = "DocLib"

#Add references to SharePoint client assemblies and authenticate to Office 365 site - required for CSOM
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"
$Password = Read-Host -Prompt "Please enter your password" -AsSecureString

#Bind to site collection
$Context = New-Object Microsoft.SharePoint.Client.ClientContext($SiteURL)
$Creds = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($User,$Password)
$Context.Credentials = $Creds

#Retrieve list
$List = $Context.Web.Lists.GetByTitle($DocLibName)
$Context.Load($List)
$Context.ExecuteQuery()

#Upload file
Foreach ($File in (dir $Folder))
{
$FileStream = New-Object IO.FileStream($File.FullName,[System.IO.FileMode]::Open)
$FileCreationInfo = New-Object Microsoft.SharePoint.Client.FileCreationInformation
$FileCreationInfo.Overwrite = $true
$FileCreationInfo.ContentStream = $FileStream
$FileCreationInfo.URL = $File
$Upload = $List.RootFolder.Files.Add($FileCreationInfo)
$Context.Load($Upload)
$Context.ExecuteQuery()
}

Brendan Griffin