How to append to system path programmatically?

Question

In python how can I programmatically append to my system path? I'm aware of sys.path.append and just searched the docs, I'm a little confused though. It tells me that sys.path.append only appends to the PYTHONPATH and not the actual system path. Is there a way I can programmatically append to the system path temporarily?

tdelaney · Accepted Answer · 2016-10-27 18:39:34Z

3

Just update the environment PATH variable:

old_path = os.environ['PATH']
try:
    os.environ['PATH'] = "{}{}{}".format('/my/new/path', os.pathsep, old_path)
finally:
    os.environ['PATH'] = old_path

Alternately, its common for programs to keep a separate environment they use when calling other tools.

env = os.environ.copy()
env['PATH'] = "{}{}{}".format('/my/new/path', os.pathsep, env['PATH'])
# change other env here...
subprocess.check_call(['my', 'tool'], env=env)

answered Oct 27, 2016 at 18:39

tdelaney

77.9k6 gold badges91 silver badges129 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Pyth0nicPenguin Over a year ago

That works perfectly, so am I correct that sys.append.path only does the PYTHONPATH itself?

xZise Over a year ago

@Pyth0nicPenguin First of all it is sys.path(.append) and yes only PYTHONPATH.

tdelaney Over a year ago

@Pyth0nicPenguin - Not quite. sys.path.append appends to the module lookup path for the running program only. If it executes other programs, they will only see the PYTHONPATH from the original environment. - And I mean execute as a child process, not import. If you execute other python scripts and want them to see a different path, you need to play the same os.environ game with PYTHONPATH.

Collectives™ on Stack Overflow

How to append to system path programmatically?

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related