Single binary

Typical computer programs have a separate binary (executable) file for each application. BusyBox is a single binary, which is a conglomerate of many applications, each of which can be accessed by calling the single BusyBox binary with various names (supported by having a symbolic link or hard link for each different name) in a specific manner with appropriate arguments.

BusyBox benefits from the single binary approach as it reduces the overheads introduced by the executable file format (typically ELF), and it allows code to be shared between multiple applications without requiring a library.

Sharing of this common code, along with routines written with size-optimization in mind, enables a BusyBox system to be much smaller than a system built with the corresponding full versions of the utilities replaced by BusyBox. The research which compared GNU, Busybox, asmutils and Perl implementations of the standard Linux commands show that in some situations BusyBox may perform faster than other implementations, but not always.