quickstart.rst: If the following instructions don't Just Work...

[tahoe.nrb at 9ox.net]

Hi,

Sorry, not being familiar with Python, I got confused between - standard 
debain package install; then that found by following quickstart:  after 
that I was left with two versions and I don't understand how to 
reconcile the two.

I installed from the debain instructions:
https://www.tahoe-lafs.org/trac/tahoe-lafs/wiki/Installation

and got:

root at Vine:~# whereis tahoe
tahoe: /usr/bin/tahoe /usr/bin/X11/tahoe /usr/share/man/man1/tahoe.1.gz
root at Vine:~# tahoe --version
allmydata-tahoe: 1.10.0

Then from this quickstart found different install instructions and a 
different version:
https://tahoe-lafs.org/trac/tahoe-lafs/browser/trunk/docs/quickstart.rst

root at Vine:/home/nrb/Downloads/allmydata-tahoe-1.10.1# bin/tahoe --version
allmydata-tahoe: 1.10.1 [master: 2875a9ffc415cd665026419001f2311b4efd44e1]

The executables look very different to me:
root at Vine:/home/nrb/Downloads/allmydata-tahoe-1.10.1# ls -la /usr/bin/tahoe
-rwxr-xr-x 1 root root 70 May  2  2014 /usr/bin/tahoe
root at Vine:/home/nrb/Downloads/allmydata-tahoe-1.10.1# ls -la bin/tahoe
-rwxr-xr-x 1 root root 4787 Jul  6 09:41 bin/tahoe

and:

root at Vine:/home/nrb/Downloads/allmydata-tahoe-1.10.1# cat /usr/bin/tahoe
#! /usr/bin/python

from allmydata.scripts import runner
runner.run()

I got as far as:
https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2429

But still not clear to me.  Can you help?

How do I replace the older system installation with the later one 
'built' from the download directory?

or

Where should I build the later one so that it is not specific to my user?

BR/ Nigel