Regarding the last error in the question:
I issue the following command in the Sage Terminal:
/cygdrive/c/Program Files/scilab-6.0.1/bin/scilab -nw
but I get bash: /cygdrive/c/Program: No such file or directory
As @Emmanuel Charpentier mentions, you should escape the space character in "Program Files".
That is, in the Sage shell, you should instead run
/cygdrive/c/Program\ Files/scilab-6.0.1/bin/scilab -nw
Note that the bash error
bash: /cygdrive/c/Program: No such file or directory
is an indication: because of the space, bash thought you were calling /cygdrive/c/Program
rather than /cygdrive/c/Program\ Files/scilab-6.0.1/bin/scilab
.
The same goes for setting the PATH in the Sage shell. What you need to add to this PATH is
/cygdrive/c/Program\ Files/scilab-6.0.1/bin
with the space in "Program Files" escaped with a backslash.
Now if you want to use Scilab from within Sage (in the Sage REPL or in the Jupyter notebook), that's it.
If you want to run the Scilab kernel for Jupyter, you should install it.
For that, in a Sage shell, run
pip install scilab_kernel
or
sage -pip install scilab_kernel
This will install the Scilab kernel, which will be located at
$SAGE_ROOT/local/share/jupyter/kernels/scilab
where $SAGE_ROOT
is the location of the Sage installation.
It also installs a scilab_kernel
module in Sage's Python, located in
$SAGE_ROOT/local/lib/python2.7/site-packages/scilab_kernel
Go edit line 93 of the file
$SAGE_ROOT/local/lib/python2.7/site-packages/scilab_kernel/kernel.py
and change it from
executable = self.executable + ' -nw'
to
executable = self.executable + ' -nwni'
Next time you launch Sage's Jupyter notebook server, you will be able to create
Jupyter worksheets with the Scilab kernel, or to change kernel to the Scilab kernel
in existing Jupyter worksheets.
I wonder whether this is a bigger issue of using outside software in the Windows solution.
I don't know if R is delivered with SageMath 8.1 or it is using the one I installed, but the interface with R is working fine.
The R interface is always tested because it's part of Sage, so it's not interfaces. Scilab is a fairly optional interface and hence not as tested and hence possibly broken ...