Termux give user write access to usb pen I have a android box that has termux and I would like to add permission for my user to write to a plugged in usb pen drive.
For what I believe I only have to add that user to sdcard_r group, I'm not really sure if this is the way.
How can I achieve this? I can't find useradd command.  

I also have tried using the termux-setup-storage command but this command doesn't seem to create a folder for my usb pen drive.  

My android version is 5.1.1
I have followed the tutorial in http://www.cnx-software.com/2012/08/26/how-to-allow-apps-to-write-files-to-usb-mass-storage-devices-in-android/ and now I can write to my usb :)