From: Philippe Bopp / temporary (
Date: Wed Nov 28 2012 - 10:58:32 CST

hi back

> The square brackets mean "optional".

you mean it's not the square bracket of tk/tcl?
very confusing!
How does one know which one is which?

> According to the link
> you've found, "the optional selection string defines how
> atoms for each frame have to be selected. If not given, as
> selection string of "user > 0" is assumed."

 very true. I want to use the option. HOW?

> In your case, this should reproduce the default behaviour:
> topo writevarxyz "" selmod "user > 0"

yea, it writes an 'empty' file, i.e. only the 2 header
lines of the xyz format

but I found another way to do it. No more writevarxyz