The disk utility in El Capitan looks to be much more limited than it used to be in older versions of mac os x. So I need to use the command line to do a lot of things now. First off is a simple format of a new disk as an plain dos disk.

yo:~ $ diskutil partitionDisk disk2 1 MBR fat32 X R
Started partitioning on disk2
Unmounting disk
Creating the partition map
Waiting for the disks to reappear
Formatting disk2s1 as MS-DOS (FAT32) with name X
512 bytes per physical sector
/dev/rdisk2s1: 490115008 sectors in 7658047 FAT32 clusters (32768 bytes/cluster)
bps=512 spc=64 res=32 nft=2 mid=0xf8 spt=32 hds=255 hid=2 drv=0x80 bsec=490234750 bspf=59829 rdcl=2 infs=1 bkbs=6
Mounting disk
Finished partitioning on disk2
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *251.0 GB   disk2
   1:                 DOS_FAT_32 X                       251.0 GB   disk2s1

This just created an empty dos disk, with the label X and using the master boot record.

I also used to format disks as regular free space so that I could easily make a bootable iso file. So I’d use this command to do that.

diskutil partitionDisk disk2 1 MBR free X R

Unfortunately, with El Capitan I haven’t been having any luck in making bootable usb drives. The dd command isn’t working the same as on older versions. So that’s one thing I need to look into.