Running an outside program (executable) in Python?

import os
path = "C:/Documents and Settings/flow_model/"
os.chdir(path)
os.system("flow.exe")

Note added by barlop

A commenter asked why this works. Here is why.

The OP's problem is os.system("...") doesn't work properly when there is a space in the path. (Note os.system can work with ('"...."') but anyhow)

Had the OP tried their program from a cmd prompt they'd have seen the error clearly.

    C:\carp>type blah.py
    import  os
    os.system(R"C:\Program Files (x86)\Google\Chrome\Application\chrome.exe")
    
    C:\carp>python blah.py
    'C:\Program' is not recognized as an internal or external command,
    operable program or batch file.
    
    C:\carp>

So it's fine for os.system("calc.exe") (there calc.exe is in the path environment variable). Or for os.system(R"c:\windows\system32\calc.exe"). There's no space in that path.

C:\>md "aa bb cc"

C:\>copy c:\windows\system32\calc.exe "c:\aa bb cc\cccalc.exe"
        1 file(s) copied.

This works (Given file "c:\aa bb cc\cccalc.exe" )

import  os 
os.chdir(R"c:\aa bb cc")
os.system("cccalc.exe")

Other options are subprocess.run and subprocess.popen.

in python 2.6 use string enclosed inside quotation " and apostrophe ' marks. Also a change single / to double //. Your working example will look like this:

import os
os.system("'C://Documents and Settings//flow_model//flow.exe'") 

Also You can use any parameters if Your program ingest them.

os.system('C://"Program Files (x86)"//Maxima-gcl-5.37.3//gnuplot//bin//gnuplot -e "plot [-10:10] sin(x),atan(x),cos(atan(x)); pause mouse"')

finally You can use string variable, as an example is plotting using gnuplot directly from python:

this_program='C://"Program Files (x86)"//Maxima-gcl-5.37.3//gnuplot//bin//gnuplot'

this_par='-e "set polar; plot [-2*pi:2*pi] [-3:3] [-3:3] t*sin(t); pause -1"'
os.system(this_program+" "+this_par)

There are loads of different solutions, and the results will strongly depend on:

• the OS you are using: Windows, Cygwin, Linux, MacOS
• the python version you are using: Python2 or Python3x

As I have discovered some things that are claimed to work only in Windows, doesn't, probably because I happen to use Cygwin which is outsmarting the OS way to deal with Windows paths. Other things only work in pure *nix based OS's or in Python2 or 3.

Here are my findings:

• Generally speaking, os.system() is the most forgiving method.
• os.startfile() is the least forgiving. (Windows only && if you're lucky)
• subprocess.Popen([...]) not recommended
• subprocess.run(winView, shell=True) the recommended way!
• Remembering that using subprocess for anything may pose a security risk.

Try these:

import os, subprocess
...
winView = '/cygdrive/c/Windows/explorer.exe %s' % somefile
...
# chose one of these:
os.system(winView)
subprocess.Popen(['/cygdrive/c/Windows/explorer.exe', 'somefile.png'])
subprocess.run(winView, shell=True)

Q: Why would you want to use explorer in Windows?

A: Because if you just want to look at the results of some new file, explorer will automatically open the file with whatever default windows program you have set for that file type. So no need to re-specify the default program to use.

for the above question this solution works.

just change the path to where your executable file is located.

import sys, string, os

os.chdir('C:\\Downloads\\xpdf-tools-win-4.00\\xpdf-tools-win-4.00\\bin64')

os.system("C:\\Downloads\\xpdf-tools-win-4.00\\xpdf-tools-win-4.00\bin64\\flowwork.exe")


'''import sys, string, os

os.chdir('C:\\Downloads\\xpdf-tools-win-4.00\\xpdf-tools-win-4.00\\bin64')

os.system(r"C:\\Downloads\\xpdf-tools-win-4.00\\xpdf-tools-win-4.00\bin64\\pdftopng.exe test1.pdf rootimage")'''

Here test1.pdf rootimage is for my code .