endianess.rs

fn main() {
  let i: u64 = 0xDEADBEEFCAFEBABE;
  let b1: u8 = ( i        & 0x00000000000000FF) as u8;
  let b2: u8 = ((i >> 8)  & 0x00000000000000FF) as u8;
  let b3: u8 = ((i >> 16) & 0x00000000000000FF) as u8;
  let b4: u8 = ((i >> 24) & 0x00000000000000FF) as u8;
  let b5: u8 = ((i >> 32) & 0x00000000000000FF) as u8;
  let b6: u8 = ((i >> 40) & 0x00000000000000FF) as u8;
  let b7: u8 = ((i >> 48) & 0x00000000000000FF) as u8;
  let b8: u8 = ((i >> 56) & 0x00000000000000FF) as u8;
  println!("b1 {}", format!("{:x}", b1));
  println!("b2 {}", format!("{:x}", b2));
  println!("b3 {}", format!("{:x}", b3));
  println!("b4 {}", format!("{:x}", b4));
  println!("b5 {}", format!("{:x}", b5));
  println!("b6 {}", format!("{:x}", b6));
  println!("b7 {}", format!("{:x}", b7));
  println!("b8 {}", format!("{:x}", b8));
}

Output on x86:

b1 be
b2 ba
b3 fe
b4 ca
b5 ef
b6 be
b7 ad
b8 de

                 DE AD BE EF    DE AD BE EF
address 0 DE <---^  |  |  |      |  |  |  ^---> EF address 0
address 1 AD <------   |  |      |  |   ------> BE address 1
address 2 BE <---------   |      |   ---------> AD address 2
address 3 EF <------------        ------------> DE address 3

           Big-Endian                    Little-Endian