Installation guide for Core - invalid command for Mac OS

[Matei Radu]

Step 8 for Mac OS of the guide "Create installation medias for Ubuntu Core" (link: https://developer.ubuntu.com/core/get-started/installation-medias) says to use dd to write the image with the following command:

sudo dd if=~/Downloads/<image file> of=<drive address> bs=32MB

While I do provide a valid paths to both image and drive, dd reports the following and does not proceed with the writing:

dd: bs: illegal numeric value

Solution: on macOS, uppercase letters to specify byte size are invalid and so I used 'm' instead of 'MB'. The guide should be updated to reflect this particularity of dd on macOS.

[David Callé (davidc3)]

Thanks for the report!