pymol installation following PyMOLWIKI instructions getting the error python2.7: can't open file 'setup.pymol': [Errno 2] No such file or directory after trying to compile and installing

What is the output of:

lsb_release -a; uname -a; python -V

Thanks

It's
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.4 LTS
Release: 16.04
Codename: xenial
Linux ST-1602L-YC1290 4.4.0-116-generic #140-Ubuntu SMP Mon Feb 12 21:23:04 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
Python 2.7.12

If you run:

sudo apt-get install pymol

Does it install OK?

yes it does.

Then the install is done..... Your question said you couldn't install it. It's in the default Ubuntu repository and I found the instruction on the pymol website

So I followed the instructions on this website
https://pymolwiki.org/index.php/Linux_Install

and tried the part entitled

Compile and install

This will install PyMOL as normal user into /opt/pymol-svn. If you don't have write permissions to /opt, change the prefix variable to something like $HOME/pymol-svn.

#!/bin/bash -e

prefix=/opt/pymol-svn
modules=$prefix/modules

# If you want to install as root, then split this line up in "build"
# and "install" and run the "install" with "sudo"
python2.7 setup.py build install \
    --home=$prefix \
    --install-lib=$modules \
    --install-scripts=$prefix

Now launch PyMOL like this:

/opt/pymol-svn/pymol

If I'm not mistaken the # is for remarks not code and this gave me the following error message
  python2.7: can't open file 'setup.py': [Errno 2] No such file or directory
hence I can't launch PyMOL using
/opt/pymol-svn/pymol

It works now. They have made it more confusing than it should be on the website https://pymolwiki.org/index.php/Linux_Install.

thank you for your help.