in an attempt to access a truecrypt container, I stumbled about the prerequisite of setting up a loop device...
ncoghlan suggested in an earlier answer
When you run it as root, losetup -f will automatically create loop devices as needed if there aren't any free ones available. So rather than doing it yourself with mknod, the easiest way to create a new loop device is with sudo losetup -f. That approach will give you a free existing loop device if one exists, or automatically create a new one if needed.
My result of "sudo losetup –f" is
losetup: –f: failed to use device: No such file or directory
Searching for this message+losetup so far does not help.
Result of "lsmod |grep loop" is
loop 28672 0
uname -r
4.5.7-200.fc23.x86_64
sudo losetup -f
requires an argument - a file to be set up as a backing storage for the loop device (the file containing your virtual disk/fs image)