Just testing markdown documentation...

show manual for radare2

$ man r2

show manual for radiff2

$ man radiff2

shows what bytes are changed and their corresponding offsets

$ radiff2 sysExecB sysExecB_1
0x0000100f 1901 => 9300 0x0000100f

used rax2 to convert the value of a hex into an int to try and see if anything was there

$ rax2 1901
0x76d
$ rax2 9300
0x2454

used radiff2 to compute the distance and the percentage of similarity between two files using the -s function

$ radiff2 -s /bin/true /bin/false
similarity: 0.996
distance: 139

used radiff2 to count the differences with the -c option

$ radiff2 -c sysExecB sysExecB_1
3083

read sysExecB ELF file's header

$ readelf -h sysExecB
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Advanced Micro Devices X86-64
  Version:                           0x1
  Entry point address:               0x454360
  Start of program headers:          64 (bytes into file)
  Start of section headers:          456 (bytes into file)
  Flags:                             0x0
  Size of this header:               64 (bytes)
  Size of program headers:           56 (bytes)
  Number of program headers:         7
  Size of section headers:           64 (bytes)
  Number of section headers:         24
  Section header string table index: 3

read sysExecB_1 ELF file's header

$ readelf -h sysExecB_1
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF64
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Advanced Micro Devices X86-64
  Version:                           0x1
  Entry point address:               0x454360
  Start of program headers:          64 (bytes into file)
  Start of section headers:          456 (bytes into file)
  Flags:                             0x0
  Size of this header:               64 (bytes)
  Size of program headers:           56 (bytes)
  Number of program headers:         7
  Size of section headers:           64 (bytes)
  Number of section headers:         24
  Section header string table index: 3