Python: get command name of Popen instance
Question:
I have an instance of the Popen class created through subprocess.Popen. I would like to get the name of that process, but I can’t find any method or instance variable that would let me get at that. For example, if I had:
p = subprocess.Popen('ls')
I would like to find a method to give me the name of the process, something that would work like:
>>> p.name()
ls
Answers:
The answer is no, until the latest versions of Python (non-stable).
Looking at the source for 3.2.3, you can see that information isn’t stored in the object (it is discarded). However, in the latest development version of Python, it has been added as subprocess.Popen.args.
So, presuming this makes it into 3.3, the only time you will see this as a feature is then. The development docs don’t mention it, but that could just be them not being updated. The fact that it’s not prefixed with an underscore (_args) implies that it is intended to be a public attribute.
If you are desperate to do this as part of the object, the easiest answer is simply to subclass subprocess.Popen() and add the data yourself. That said, I really don’t think it’s worth the effort in most cases.
>>> class NamedPopen(Popen):
... def __init__(self, cargs, *args):
... Popen.__init__(self, cargs, *args)
... self.args = cargs
...
>>> x = NamedPopen("ls")
>>> x.args
'ls'
As mentioned by Lattyware, If you’re making the Popen call yourself, you can just save it then to retrieve later. You don’t actually need a container class to use do this, as you can just store it in the instance’s internal dict:
>>> import subprocess
>>>
>>> to_exec = 'ls'
>>> p = subprocess.Popen(to_exec)
>>> p.name = to_exec
and then later:
>>> p.name
'ls'
>>>
This question is quite old, and the earlier answers are increasingly stale. In more recent versions of Python, p.args contains the command line if you ran p = subprocess.Popen(something). According to the documentation, this was added in Python 3.3.
Perhaps separately notice that you should now prefer subprocess.run() for all the use cases it can handle; raw Popen requires you to add several lines of boilerplate around it, some of which are sometimes hard to get right (and of course, why spend the effort when the library already provides a robust, tested convenience function).
Analogously to the case for Popen above, the CompletedProcess object returned by subprocess.run has an .args member which contains the command line used to start the process. This was apparently introduced in Python 3.5.
I have an instance of the Popen class created through subprocess.Popen. I would like to get the name of that process, but I can’t find any method or instance variable that would let me get at that. For example, if I had:
p = subprocess.Popen('ls')
I would like to find a method to give me the name of the process, something that would work like:
>>> p.name()
ls
The answer is no, until the latest versions of Python (non-stable).
Looking at the source for 3.2.3, you can see that information isn’t stored in the object (it is discarded). However, in the latest development version of Python, it has been added as subprocess.Popen.args.
So, presuming this makes it into 3.3, the only time you will see this as a feature is then. The development docs don’t mention it, but that could just be them not being updated. The fact that it’s not prefixed with an underscore (_args) implies that it is intended to be a public attribute.
If you are desperate to do this as part of the object, the easiest answer is simply to subclass subprocess.Popen() and add the data yourself. That said, I really don’t think it’s worth the effort in most cases.
>>> class NamedPopen(Popen):
... def __init__(self, cargs, *args):
... Popen.__init__(self, cargs, *args)
... self.args = cargs
...
>>> x = NamedPopen("ls")
>>> x.args
'ls'
As mentioned by Lattyware, If you’re making the Popen call yourself, you can just save it then to retrieve later. You don’t actually need a container class to use do this, as you can just store it in the instance’s internal dict:
>>> import subprocess
>>>
>>> to_exec = 'ls'
>>> p = subprocess.Popen(to_exec)
>>> p.name = to_exec
and then later:
>>> p.name
'ls'
>>>
This question is quite old, and the earlier answers are increasingly stale. In more recent versions of Python, p.args contains the command line if you ran p = subprocess.Popen(something). According to the documentation, this was added in Python 3.3.
Perhaps separately notice that you should now prefer subprocess.run() for all the use cases it can handle; raw Popen requires you to add several lines of boilerplate around it, some of which are sometimes hard to get right (and of course, why spend the effort when the library already provides a robust, tested convenience function).
Analogously to the case for Popen above, the CompletedProcess object returned by subprocess.run has an .args member which contains the command line used to start the process. This was apparently introduced in Python 3.5.