The Pkg scripts were partly inspired by the versatility of the slackware pkgtools scripts, which are also written in Bourne-compatible dialect. However, the Pkg scripts were a radical departure from pkgtools in form and function, with (mostly) POSIX-compliant syntax and a more centralized set of functionality.
While the pkgtools scripts perform most of their functions under the impression that the key information about the package lies with its filename, the Pkg scripts looked inside package files to determine their critical features.
The Pkg scripts also provided an automated package compilation process, which uses user-created shell scripts (build files) to generate packages from source. Alongside the traditional file-based utilities is a simple utility (pkg) that handles packages, repositories, and dependencies in a straightforward manner.