yum syntax error?

usao · 06-16-2017, 09:54 AM

CentOS 7.3
Started getting a syntax error from the yum command... Any suggestions other than rolling back to Pythoh 2.7?

Code:

# yum update -y
  File "/usr/bin/yum", line 30
    except KeyboardInterrupt, e:
                            ^
SyntaxError: invalid syntax

The /usr/bin/yum appears to be a python script.
The error started after I upgraded to Python 3.5.2.

Code:

# python -V
Python 3.5.2

Demosa · 06-16-2017, 10:10 AM

Odd, can you run

Code:

yum info yum

I doubt it's python

usao · 06-16-2017, 10:35 AM

No, same issue.
When I switch back to python 2.7 yum works correctly.

pan64 · 06-16-2017, 10:39 AM

switch back from where? python 3.x and 2.x are not compatible with each other.

rknichols · 06-16-2017, 10:47 AM

/usr/bin/yum is most definitely a Python script, but it's for Python 2. If you installed Python 3 in place of Python 2, or made Python 3 the default, that's going to break many things on your system. You can install Python 3.x alongside Python 2, but Python 2 needs to remain the default. There is a Python 3.4 package (python34-3.4.5-4.el7) available for CentOS 7 from the epel repo. I don't know of any Python 3.5 package that has been built for CentOS.

usao · 06-16-2017, 11:05 AM

I have both versions of python installed. The default CentOS 7.3 is Python 2.7, while I also installed Python 3.5.2.
When the root account is configured to use Python 3.5.2 I get the 'yum' error as shown above. When I switch back to using Python 2.7 then 'yum' works.

rknichols · 06-16-2017, 11:25 AM

It's a basic "Doc, it hurts when I do this," : "Don't do that" issue. If you set up an environment to use Python 3.x, then any system Python scripts you launch from that environment are going to fail.

usao · 06-16-2017, 11:39 AM

How can one identify the necessary fixed to get CentOS 7.3 to work properly with the installed Python version?
Version 2.7 is horribly out of date, and even 3.5.2 is still out of date and needs to get pushed further forward.
This seems to be a flaw in the design of CentOS in that it's using critically out of date software and doesn't appear to be making any effort to bring things up to proper levels.
Many places I have researched on the web are saying to get off 2.7 as soon as possible, but it seems the OS it tied to this out of date version.
This needs to get addressed as soon as possible.

pan64 · 06-16-2017, 11:48 AM

Why do you think that? python 2.x and 3.x are not compatible with each other, and 2.x is not outdated at all. see for example here: https://www.python.org/downloads/
CentOS is not tied to python 2, but huge amount of apps are implemented using python 2 and actually (almost) impossible to reimplement all of them with python 3 quickly. This is valid for all linux distros including debian, ubuntu, centos and (almost) all of them.

DavidMcCann · 06-16-2017, 12:31 PM

Quote:

Originally Posted by usao

This seems to be a flaw in the design of CentOS in that it's using critically out of date software and doesn't appear to be making any effort to bring things up to proper levels.

CentOS is basically a free version of Red Hat. People who run their businesses with RHEL don't want the latest stuff, they want the tried and tested stuff. The same goes for most CentOS users (who run half the internet). If you try to make CentOS "up-to-date" you will have problems. If you feel that you really need to do it, then it's probably a sign that you shouldn't be using CentOS in the first place!