If you freeze bacon, then thaw it out after it's expiration date, how long is it good for?
up vote 3 down vote. A .o object file file (also .obj on Windows) contains compiled object code (that is, machine code produced by your C or C++ compiler), together with the names of the functions and other objects the file contains. Object files are processed by the linker to produce the final executable.
Source code is often packed for download as a TAR (Tape ARchive) file, that is a standard format in the Unix/Linux world. These files have a .tar extension; they can also be compressed, the extension is .tar.gz or .tar.bz2 in these cases. There are several ways to unpack these files.