macos iso to usb copy

mulder@~/Project/obs$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage Macintosh HD            499.4 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk1 (internal, virtual):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Macintosh HD           +499.1 GB   disk1
                                 Logical Volume on disk0s2
                                 654DFEA3-6230-4387-9EBE-06E807DB406C
                                 Unencrypted
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *64.2 GB    disk2
   1:             Windows_FAT_32                         64.2 GB    disk2s1
 mulder@~$ cd Downloads/
mulder@~/Downloads$ find . -name "*.iso"
./ubuntu-14.04.4-server-amd64.iso
mulder@~/Downloads$ sudo dd if=./ubuntu-14.04.4-server-amd64.iso  of=/dev/disk2s1 bs=1m
Password:
579+0 records in
579+0 records out
607125504 bytes transferred in 26.253698 secs (23125333 bytes/sec)
mulder@~/Downloads$