I'm just about to release 1.0.2. which includes a rudimentary "help" command.
I expect to expand on this greatly, but for now it prints out the URL on http://www.xmlsh.org associated with the command, and on browser enabled systems launches the default browser (Using the Java Desktop class) pointing to the associated help page.
This works for all builtin, internal, and supplimentary commands as well as extension modules.
I went back and forth literally dozens of times in my mind about how best to do this. I almost implemented it using Java annotations which would have been really cool ...
but got stuck on how to cleanly annotate script based commands. Some commands are actually .xsh scripts not .java classes so these would need an ancillary annotation method.
I finally tossed that whole idea (and implementation) and settled on a help.xml file per package. Right now this just contains the command name and URL, but I expect to enahnce it to provide usage text (text based only) and maybe short help text for each command.
I dont expect to ever provide full text formatted help text (in pure text form) because the state-of-the-art for formatted documents has just evolved past plain text. Gone are the days of nroff, and -man. They still exist ... but I dont want to move back to that technology, especially since its impossible to write a good terminal app using Java. (lack of the basics for console IO such as unbuffered charactor reading, clearing screens, cursor positioning).
I want the best of both worlds ! A docbook sourced help system that can generate HTML, PDF and TEXT yes plain TEXT ! But alas ... its even againsted my stated philosophy to go back to text. Can win for loosing :)
Also coming is a very simplistic more command. The best that can be done without unbuffered console IO. (have to hit ENTER to read characters in java. 10 year old bug that sun refuses to belive is important).