ARJ

ARJ (Archived by Robert Jung) is a software tool designed in 1991 by Robert K. Jung for creating high-efficiency compressed file archives. ARJ is currently on version 2.86 for MS-DOS and 3.20 for Microsoft Windows and supports 16-bit, 32-bit and 64-bit Intel architectures.

ARJ was one of many file compression utilities for MS-DOS and Microsoft Windows during the early and mid-1990s. Parts of ARJ were covered by (expired). ARJ is well-documented and includes over 150 command line switches.

File format support in other software
ARJ archives can be unpacked with various tools other than the ARJ software. There exists a free software re-implementation of the tool. A number of software utilities, including 7-Zip, Zipeg, and WinRAR can also unpack .arj files. For macOS, standalone utilities, such as DeArj and UnArjMac, are available.