An efficient compression program that used to be PKZip's main rival around 1992-1994, developed by Robert K. Jung. ARJ was ported to most platforms, including Amiga, and in some cases offered better compression ratio than ZIP or LZH. It's main claim to fame was its huge popularity amongst European computer users, hence its ever-lasting presence on the warez scene.
Here's the splash screen from an old version of ARJ, before it was purchased and re-purchased by a couple of corporations:
ARJ 2.30 Copyright (c) 1990-92 Robert K Jung. Jan 19 1992
NOT REGISTERED for business, commercial, or government use.
All Rights Reserved. ARJ file compression archiver utility.
List of frequently used commands and switches. Type ARJ -? for more help.
Usage: ARJ < command > (-< sw > (- < sw >...)) < archive_name > (file_names...)
Examples: ARJ a -r -wtemp software , ARJ l software , ARJ e software readme
a: Add files to archive m: Move files to archive
d: Delete files from archive t: Test integrity of archive
e: Extract files from archive u: Update files to archive
f: Freshen files in archive v: Verbosely list contents of archive
l: List contents of archive x: eXtract files with full pathname
c: skip time-stamp Check n: only New files (not exist)
d: with Delete (move) r: Recurse subdirectories
e: Exclude paths from names u: Update files (new and newer)
f: Freshen existing files v: enable multiple Volumes
g: Garble with password w: assign Work directory
i: with no progress Indicator x: eXclude selected files
m: with Method 0, 1, 2, 3, 4 y: assume Yes on all queries
... and then Eugene Roshal's RAR came along ...