Python: subprocess with different working directory

python subprocess working-directory
pepero picture pepero · Sep 21, 2010 · Viewed 37.4k times · Source

I have a python script that is under this directory:

work/project/test/a.py

Inside a.py, I use subprocess.POPEN to launch the process from another directory,

work/to_launch/file1.pl, file2.py, file3.py, ...

Python Code:

subprocess.POPEN("usr/bin/perl ../to_launch/file1.pl")

and under work/project/, I type the following

[user@machine project]python test/a.py,

error "file2.py, 'No such file or directory'"

How can I add work/to_launch/, so that these dependent files file2.py can be found?

Answer

eumiro picture eumiro · Sep 21, 2010

Your code does not work, because the relative path is seen relatively to your current location (one level above the test/a.py).

In sys.path[0] you have the path of your currently running script.

Use os.path.join(os.path.abspath(sys.path[0]), relPathToLaunch) with relPathToLaunch = '../to_launch/file1.pl' to get the absolute path to your file1.pl and run perl with it.

EDIT: if you want to launch file1.pl from its directory and then return back, just remember your current working directory and then switch back:

origWD = os.getcwd() # remember our original working directory

os.chdir(os.path.join(os.path.abspath(sys.path[0]), relPathToLaunch))
subprocess.POPEN("usr/bin/perl ./file1.pl") 
[...]

os.chdir(origWD) # get back to our original working directory

Related questions

How to call an external command?

How do you call an external command (as if I'd typed it at the Unix shell or Windows command prompt) from within a Python script?

Read More
Running shell command and capturing the output

I want to write a function that will execute a shell command and return its output as a string, no matter, is it an error or success message. I just want to get the same result that I would have …

Read More
Store output of subprocess.Popen call in a string

I'm trying to make a system call in Python and store the output to a string that I can manipulate in the Python program. #!/usr/bin/python import subprocess p2 = subprocess.Popen("ntpq -p") I've tried a few things including …

Read More