Identifying RPM files with the file(1) command

The magic file on most UNIX-like systems today should have the necessary information to identify RPM files. But in case your system doesn't, the following information can be added to the file:
#------------------------------------------------------------------- # # RPM: file(1) magic for Red Hat Packages # 0 beshort 0xedab >2 beshort 0xeedb RPM >>4 byte x v%d >>6 beshort 0 bin >>6 beshort 1 src >>8 beshort 1 i386 >>8 beshort 2 Alpha >>8 beshort 3 Sparc >>8 beshort 4 MIPS >>8 beshort 5 PowerPC >>8 beshort 6 68000 >>8 beshort 7 SGI >>10 string x %s

The output of the file command is succinct:
# file baz baz: RPM v3 bin i386 vlock-1.0-2 #

In this case, the file called baz is a version 3 format RPM file containing release 2 of version 1.0 of the vlock package, which has been built for the Intel x86 architecture.