What Does a Python Process Return Code -9 Mean

what does python 3.6 subprocess.Popen().returncode of 100 means?

looks like you got your 100 returncode from apt-get install command :

E: Unable to locate package ubuntu-restricted-extra

Why does subprocess.run create return code 1 even if the command was successful?

It totally depends on the value returned by your program with different arguments.

For example, when I run the following on my computer (git is installed):

result = subprocess.run(['git'], capture_output=True)

result.returncode is 1

If I run git with parameter --version like this:

result = subprocess.run(['git','--version'], capture_output=True)

result.returncode is 0

To really check if a program exists or not (on Windows) you could do something like:

try:
    result = subprocess.run(['choco'], capture_output=True)
    print(result)
except FileNotFoundError:
    print("Program not installed")

Check out this official documentation on Subprocess

Python 'return not' statement in subprocess returncode

not is a boolean operator that returns the boolean inverse of the value. return returns the result of that operator. In other words, the expression should be read as return (not self.myReturnCode). Quoting the documentation:

The operator not yields True if its argument is false, False otherwise.

If self.myReturnCode is a true value, not self.myReturnCode is False, and vice versa. Note that self.myReturnCode can be any Python value, but not always returns a boolean value, either True or False.

If externalProcessPopen.returncode is the return code of an external process, then it'll be a positive integer if the process exited with an error, 0 if it exited successfully. This is called the process exit status; what non-zero values are returned depends entirely on the process. not 0 is then True, not 1 (or a higher integer value) gives you False.

If it is None, then True (not None is True) would be returned as well, but a subprocess.Popen() return code is only None if the process has not yet exited.

Python error codes

Are you getting the exit status from mysubproc.returncode?

From http://docs.python.org/library/subprocess.html#subprocess.Popen.returncode:

A negative value -N indicates that
the child was terminated by signal N
(Unix only).

Signals 6 & 11 are SIGABRT (abort) and SIGSEGV (segfault) ( http://linux.die.net/man/7/signal ). My guess is that those other scripts are running into badness with an extension or one of the libraries that an extension depends on. You may have a bad build then - either recompile if you did so manually or see if there's an updated package.

Python Forcing Subprocess To Fail and Get A Return Code Of Not Zero

Even if you could get this to work, your users are going to hate you for telling them there are syntax errors in their script, but not what or where they are.

So forget about subprocess and use the built-in compile function instead:

    script = 'print(0'
    try:
        compile(script, '<string>', 'exec')
    except SyntaxError as exception:
        # do something user-friendly with exception...
    else:
        # syntax seems okay! run script...

Don't be fooled by the 'exec' argument: this only specifies the kind of code the script contains. If there are no syntax errors, compile returns a code object.

How to return status code in Python without actually exiting the process?

Wait until the end of your loop to return the 1 exit code. I'd do it like:

def process_pdf_dir() -> int:
    ret = 0
    for file in os.listdir('pdf_files/'):
        if file.endswith('.pdf'):

            if not anonymiser(file):
                # remember to return a warning
                ret = 1

            if criticalError:
                # immediately return a failure
                return 2
    return ret

if __name__ == '__main__':
    sys.exit(process_pdf_dir())

If "critical error" includes uncaught exceptions, maybe put that outside of process_pdf_dir, e.g.:

if __name__ == '__main__':
    try:
        sys.exit(process_pdf_dir())
    except:
        sys.exit(2)

Return code of subprocess.run when using shell pipes

This doesn't do what you think:

>>> subprocess.run(['false', '|', 'true'], shell=True)

When you pass a list of strings to subprocess.run and specify shell=True, only the first item is interpreted as a command (the remaining items are provided as arguments to the shell). Compare the output of:

>>> subprocess.run('echo hello world', shell=True)
hello world
CompletedProcess(args='echo hello world', returncode=0)

With:

>>> subprocess.run(['echo', 'hello', 'world'], shell=True)

CompletedProcess(args=['echo', 'hello', 'world'], returncode=0)

With:

>>> subprocess.run(['echo $0 $1', 'hello', 'world'], shell=True)
hello world
CompletedProcess(args=['echo $0 $1', 'hello', 'world'], returncode=0)

So what you have there is equivalent to:

>>> subprocess.run('false', shell=True)

And do you know why the return codes of subprocess.run('false | true', shell=True) and subprocess.run(['false', '|', 'true']) are different?

Because the first runs false | true, which is a pipeline. The exit code of a pipeline is the exit code of the last command in the pipeline (in this case true). The second call, as discussed here, just runs false.

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