To determine the format of an operating system executable file, such as an object file (.o file) or a shared object file (.so file), use the UNIX file command. For example:
file myobj.o
displays one of the following on a Solaris SPARC machine
myobj.o: ELF 32-bit MSB relocatable SPARC version 1 myobj.o: ELF 64-bit MSB relocatable SPARCV9 version 1