Are the open source implementations of Rexx widely adopted? This article highlights them, but I don't think I've ever run across them. It would be interesting to hear about where these have been adopted, relative to other scripting languages that fill a similar niche (presumably mostly Python, Perl, and sh)?

(Apropos of nothing else, it seems worth noting that Rexx is a product within IBM's suite and that this website appears to be owned by Red Hat, now an IBM subsidiary.)