Find path to pdf-reader and open file with it

Question

OS : Linux.

What I want to do: Compile a file with TikZ-commands and open it with a certain pdf-viewer (I have to work only with the name of the viewer!). If the viewer does not exist, I have to return an exception.

My approach: I search for a file with the name of the viewer. This then should be the viewer itself. Next, I want to determine the path to this file. tikz_commands. Then I want to use its value via subprocess.call([viewer_path] + ['tikz_commands.pdf']. The following is part of a class:

import subprocess
import os 
import tempfile
import fnmatch

def visualize(self,viewername):

    temp = tempfile.mkdtemp()
    os.chdir(temp)

    file = open('tikz_commands.tex', 'w')
    file.write(tikz_commands)
    file.close()

    proc=subprocess.Popen(['pdflatex','tikz_commands.tex'])
    proc.communicate()

    subprocess.call([str(self.set_viewer(viewername)), 'tikz_commands.pdf'])

 def set_viewer(self,viewername):
    try:
        for root, dirs, files in os.walk(os.path.join('path', 'to', 'file')):
            for file in files:
                if str(viewername) in file.lower():
                    return(os.path.join(root, file))
    except NameError:
        print('No such viewer')

Can this work?

Have I overlooked a much easier approach?

Any help is much appreciated!

EDIT: Thanks to @Roland Smith and @Robb I could work everything out and it works perfectly now. Comment if you want to see the final code.

Answer 1

On UNIX-like operating systems (like Linux) it is generally expected that such a program is installed in a location that is contained in the environment variable PATH. In that case you should just be able to call the program without any location and it should just work.