About .ARJ File Format
To do word count in ARJ archives, let’s get to know a little more about this format.
ARJ (Archived by Robert Jung) was designed by Robert K. Jung for creating high-efficiency compressed file archives.
It was the main rival archiver of PKZIP during the early and mid-1990s. While less popular than PKZIP, it did have a niche market during the BBS era. This was thanks to its more robust creation and handling of multi-volume archives (more suited for slow connections).
Many modern software utilities can create, modify or open ARJ files, notably 7-Zip, Zipeg and WinRar.
Link:
7-Zip Home Page
WinRAR Home Page