[ANN] CommandShell 4.2.1

CommandShell 4.2.1 is now on SqueakMap and the Squeak 3.10 Universe.

- Home page: http://wiki.squeak.org/squeak/1914
- CommandShell overview: http://wiki.squeak.org/squeak/2153
- Using Squeak as a unix shell: http://wiki.squeak.org/squeak/6023

This is a substantial rewrite of CommandShell 3. It uses event driven
I/O when the AioPlugin is available; otherwise it relies on polling
loops similar to CommandShell 3. Shell syntax is now separated from
the CommandShell, and different views permit graphical windows based
on Transcript (Morphic and MVC), or an external teletype style view
for interacting with a headless Squeak from a command line.

CommandShell 4.2.1 works with GraphViz, but has not been tested with
any other packages that may depend on it.

OSProcess version 4.3.5 or greater is recommended, as a concurrency
bug has been addressed that previously caused intermittent failures
in the CommandShell test suite. If AioPlugin is used, version 2.2 or
greater is recommended. Earlier versions had a bug that limited the
number of file handles to 19, causing intermittent problems in the
CommandShell test suite. Note that AioPlugin may not be included
with your VM, even if OSProcessPlugin is present. VM builders
may find AioPlugin, OSProcessPlugin, and XDisplayControlPlugin on
SqueakMap, SqueakSource, and on the swiki.

The MVC environment is broken on some Squeak images (notably
Squeak 3.10), so CommandShell does not work under MVC in those
images.

The prior version (CommandShell 3.0.5) remains available on SqueakMap
and the Squeak 3.10 Universe.

- Dave