Hi Liz,
The link you sent is to the Chimera documentation, not ChimeraX.  They are two different programs. The ChimeraX documentation is included with your download (menu: Help… User Guide) or see the development copy on our website:
<http://www.rbvi.ucsf.edu/chimerax/docs/user/index.html>

However, I have no idea what’s going on with what you entered, because there IS a nucleotides command in recent versions of ChimeraX, with syntax slightly different than in Chimera. 
<http://www.rbvi.ucsf.edu/chimerax/docs/user/commands/nucleotides.html>

In the current daily build of ChimeraX, there are also a few nucleotides variants in the Preset menu, and in the Toolbar, a whole tab of icons for nucleotide display styles.

I hope this helps,
Elaine
-----
Elaine C. Meng, Ph.D.
UCSF Chimera(X) team
Department of Pharmaceutical Chemistry
University of California, San Francisco

> On May 22, 2019, at 11:32 AM, Liz Kellogg <lizkellogg@gmail.com> wrote:
>
> Hi ChimeraX users,
>
> I am dabbling around in ChimeraX, and it seems that the documentation doesn't quite match up with the commands that are available. For example, this command: nucleotides https://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/nucleotides.html
> would be useful, but when I enter this into the command line it says "unknown command"
> I downloaded the nightly chimerax build for mac, so it can't be a problem with an out of date version. Is this command not currently implemented? and if not, how many commands are listed in the documentation that aren't implemented?
>
> Best
> Liz
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