Python exit codes

Question

Where can I find information about meaning of exit codes of "python" process on Unix? For instance, if I do "python thisfiledoesntexist.py", I get exit code 2

Summary:

from errno import errorcode
print errorcode[2]

Answer 1

As stated, mostly the error codes come from the executed script and sys.exit().

The example with a non-existing file as an argument to the interpreter fall in a different category. Though it's stated nowhere I would guess, that these exit codes are the "standard" Linux error codes. There is a module called errno that provides these error numbers (the exit codes come from linux/include/errno.h.

I.e.: errno.ENOENT (stands for for "No such file or directory") has the number 2 which coincides with your example.

Answer 2

The Python manual states this regarding its exit codes:

Some systems have a convention for assigning specific meanings to specific exit codes, but these are generally underdeveloped; Unix programs generally use 2 for command line syntax errors and 1 for all other kind of errors.

So, since you specified thisfiledoesntexist.py as a command line argument, you get a return code of 2 (assuming the file does not, in fact, exist. In that case I'd recommend renaming it to thisfiledoesexist.py. ;) )

Other that such parsing errors, the return code is determined by the Python program run. 0 is returned unless you specify another exit code with sys.exit. Python itself does not interfere.

Answer 3

Maybe exit code constants from os module can help you. Also have a look at sys.exit documentation.

Answer 4

Unfortunately, there is no 100% guarantee that Python's exit codes will be what the documentation claims they will be: os._exit allows the Python programmer to define which exit code is supposed to be used, which means python file_exists_but_claims_that_it_does_not.py could exit with os.EX_DATAERR.