How do I enable python35 from Software Collections at login?

Question

I followed the Software Collections Quick Start and I now have Python 3.5 installed. How can I make it always enabled in my ~/.bashrc, so that I do not have to enable it manually with scl enable rh-python35 bash?

Answer 1

Use the scl_source feature.

Create a new file in /etc/profile.d/ to enable your collection automatically on start up:

$ cat /etc/profile.d/enablepython35.sh
#!/bin/bash
source scl_source enable python35

See How can I make a Red Hat Software Collection persist after a reboot/logout? for background and details.

Answer 2

This answer would be helpful to those who have limited auth access on the server.

I had a similar problem for python3.5 in HostGator's shared hosting. Python3.5 had to be enabled every single damn time after login. Here are my 10 steps for the resolution:

1. Enable the python through scl script python_enable_3.5 or scl enable rh-python35 bash.

2. Verify that it's enabled by executing python3.5 --version. This should give you your python version.

3. Execute which python3.5 to get its path. In my case, it was /opt/rh/rh-python35/root/usr/bin/python3.5. You can use this path to get the version again (just to verify that this path is working for you.)

4. Awesome, now please exit out of the current shell of scl.

5. Now, lets get the version again through this complete python3.5 path /opt/rh/rh-python35/root/usr/bin/python3.5 --version.

   It won't give you the version but an error. In my case, it was

/opt/rh/rh-python35/root/usr/bin/python3.5: error while loading shared libraries: libpython3.5m.so.rh-python35-1.0: cannot open shared object file: No such file or directory

6. As mentioned in Tamas' answer, we gotta find that so file. locate doesn't work in shared hosting and you can't install that too.

   Use the following command to find where that file is located:

find /opt/rh/rh-python35 -name "libpython3.5m.so.rh-python35-1.0"

7. Above command would print the complete path (second line) of the file once located. In my case, output was

find: `/opt/rh/rh-python35/root/root': Permission denied
/opt/rh/rh-python35/root/usr/lib64/libpython3.5m.so.rh-python35-1.0

8. Here is the complete command for the python3.5 to work in such shared hosting which would give the version,

LD_LIBRARY_PATH=/opt/rh/rh-python35/root/usr/lib64 /opt/rh/rh-python35/root/usr/bin/python3.5 --version

9. Finally, for shorthand, append the following alias in your ~/.bashrc

alias python351='LD_LIBRARY_PATH=/opt/rh/rh-python35/root/usr/lib64 /opt/rh/rh-python35/root/usr/bin/python3.5'

10. For verification, reload the .bashrc by source ~/.bashrc and execute python351 --version.

Well, there you go, now whenever you login again, you have got python351 to welcome you.

This is not just limited to python3.5, but can be helpful in case of other scl installed softwares.