Need to convert multiple .NEF files to the JPEG format? You can easily do this from the command line using the UFRaw tool. First off, install the UFRaw package on your system. UFRaw is available in the software repositories of many popular Linux distributions, so you can install it using your distro’s package manager. On Ubuntu, use the following command:
sudo apt-get install ufraw
Launch then the terminal, switch to the directory containing NEF files, and run the following command:
ufraw-batch --out-type=jpeg --out-path=./jpg ./*.NEF
That’s all there is to it.