I have made good progress today, thanks to the help of this list.  Thanks!

I can now run the example on the First Document web page, running ConTeXt from the command line.  That works perfectly.

When I try to run the same file from within TeXShop, however, it tells me:

!  Undefined control sequence.
l.2  \startsection
[title={Testing ConTeXt}]
?

I have created the file "ConTeXt Suite.engine" in directory ~/Library/TeXShop/Engines, per the instructions on the Mac Installation web page.

So I am not sure why TeXShop does not know about \startsection.  I would be grateful for your advice on this.

Sincerely,
Bruce


On Dec 15, 2015, at 12:17 PM, Boghosian, Bruce <bruce.boghosian@tufts.edu> wrote:

Dear Mojca:

On Dec 15, 2015, at 10:20 AM, Mojca Miklavec <mojca.miklavec.lists@gmail.com> wrote:

[...]

... oh, and I just noticed one more thing that might be causing the
problem. You also need to remove the TEXMF variable.

That fixed it!!!

Thanks very much to everybody for all the informative help and advice.

Best regards,
Bruce

Bruce M. Boghosian
Professor, Department of Mathematics, Tufts University
Bromfield-Pearson Hall, Medford, Massachusetts 02155, USA