I needed to mount an .iso file this morning, which I’ve done dozens of times in Linux, and I realized the command I’d normally use in Linux does not work. For example:

Linux

mount -o loop image.iso /mnt

This works fine in Linux and lets you “mount” the .iso file as if it were burned and in the drive. This does not work on FreeBSD. You get an error like:

mount: image.iso mount option is unknown: Invalid argument

FreeBSD

The solution (the only one I’ve found so far) is to use a much more in-depth command like:

mount_cd9660 -o ro /dev/$(mdconfig -a -t vnode -f /path/to/file.iso) /mount-point

Hopefully this little note helps someone else have less trouble than I did in mounting .iso images in FreeBSD.