How To Root Galaxy Grand Duos I9082?
Installing Recovery:
Download Drivers for your device: download from this thread.
Download Recovery from this link and Odin flashing tool from here.
Boot your device into download mode. Press and hold (Vol Down + Power + Home Button) and wait for boot.
Extract the "WM-touch_i9082_chotu.tar.zip"
Click PDA Tab and select "CWM-touch_i9082_chotu.tar.md5" file that is obtained from extracting the zip package.
Auto Reboot and F.Reset Time should be tick marked.
Click START and wait for the flash to complete.
Rooting and Flashing SU:
Download SuperSU --> here.
Transfer the downloaded file to the external
memory of your device.
Turn off the device, boot into recovery. Press and hold Vol UP + Power + Home Button.
Select "Install zip from SD Card" >> "Choose zip from SD Card" >> now select the "UPDATE-SuperSU-v1.05.zip" file.