You need to download the file first.
Assuming you are on a Windows that supports powershell and you are using batch (otherwise just use Powershell and directly use the command in quotes):
powershell -Command "(New-Object Net.WebClient).DownloadFile('http://www.example.com/text.txt', 'txtfile.txt')"
for /f "tokens=*" %%A in (txtfile.txt) do (echo%%A)
The 2nd line will download the
text.txt file from the specified link and save it as
txtfile.txt in the same directory.
EDIT: If you have a newer Windows version that supports PowerShell 3.0 and up, check @rahuldottech's answer, it's simpler and faster.