File type identification is done using -I. With this option, rabin2 prints information on a binary type, like its encoding, endianness, class, operating system:
$ rabin2 -I /bin/ls
arch x86
binsz 128456
bintype elf
bits 64
canary true
class ELF64
crypto false
endian little
havecode true
intrp /lib64/ld-linux-x86-64.so.2
lang c
linenum false
lsyms false
machine AMD x86-64 architecture
maxopsz 16
minopsz 1
nx true
os linux
pcalign 0
pic true
relocs false
relro partial
rpath NONE
static false
stripped true
subsys linux
va true
To make rabin2 output information in format that the main program, radare2, can understand, pass -Ir option to it:
$ rabin2 -Ir /bin/ls
e cfg.bigendian=false
e asm.bits=64
e asm.dwarf=true
e bin.lang=c
e file.type=elf
e asm.os=linux
e asm.arch=x86
e asm.pcalign=0
