xcode_6.1.1.dmg md5 hash

xcode_6.1.1.dmg.md5

md5
00773faa3ddc9a0b7b94bab8496aa522  xcode_6.1.1.dmg

dmg2img

md5
54888ae7ba8640eef1906f5a5cd4b55e  xcode_6.1.1.img

hexdump -C xcode_6.1.1.img | grep --max-count=1 "48 2b 00 04"

00008400  48 2b 00 04 80 00 01 00  31 30 2e 30 00 00 00 00  |H+......10.0....|

00008400 hex
33792 decimal
33792 - 1024 = 32768

( Instructions found at http://linuxforums.org.uk/index.php?topic=1072.0 )

file xcode_6.1.1.img

xcode_6.1.1.img: 
Apple Driver Map, blocksize 2048, blockcount 2153131, devtype 0, devid 0, descriptors 0, contains[@0x800]: 
Apple Partition Map, map block count 3, start block 1, 		  block count 15, 		  name Apple, 	  type Apple_partition_map, contains[@0x1000]:
Apple Partition Map, map block count 3, start block 16, 	  block count 2153112, 	name disk image,type Apple_HFS, contains[@0x1800]:
Apple Partition Map, map block count 3, start block 2153128,block count 3, 			                  type Apple_Free

sudo losetup -o 32768 /dev/loop0 xcode_6.1.1.img

apt-cache search hfs

sudo apt-get install hfsutils

sudo mount -t hfsplus /dev/loop0 ~/Volumes/Xcode

tar -C ~/Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/ -czf MacOSX10.9.sdk.tar.gz MacOSX10.9.sdk

sudo umount Volumes/Xcode

sudo losetup --detach-all

breadcrumb http://unix.stackexchange.com/questions/101561/what-are-the-differences-between-bsdtar-and-gnu-tar
the file size is not the same when created with linux vs created with osx