Should I have removed `(shell . t)` to clear an ob-shell initialization error?

Question

First post. I'd like to confirmation whether I sucessfully troubleshooted an install of Emacs, and, if I didn't, direction on where and how to proceed.

My setup:

• Emacs 24.5
• Macbook Pro Core Duo (mid-2010)
• OSX El Cap (10.11.4)

I recently installed Emacs along with Kierian Healy's [https://kieranhealy.org/resources/emacs-starter-kit/](social science starter kit). When I first launched Emacs after the installation I received an error (below) that as far as I could tell, didn't prevent anything from working—although, given that I'm new to Emacs one can never be sure.

Once installed, I received the follwing error message at launch:

Warning (initialization): An error occurred while loading     
`/Users/lmp/.emacs.d/init.el':

File error: Cannot open load file, no such file or directory, ob-shell

To ensure normal operation, you should investigate and remove the
cause of the error in your initialization file.  Start Emacs with
the `--debug-init' option to view a complete error backtrace.

I launched Emacs from the terminal into debug mode but couldn't for the life of me figure out the backtrace. So I commented out sections of my init.el file until I found the problem line of code:

(org-babel-load-file (expand-file-name "starter-kit.org" dotfiles-dir)) 

So I opened the starter-kit.org file and do the same which leads me to the following code

(org-babel-do-load-languages
'org-babel-load-languages
'((emacs-lisp . t)
(shell . t)))

After searching the org-mode website and a few forums, I tried the following that cleared the error:

(org-babel-do-load-languages
'org-babel-load-languages
'((emacs-lisp . t)))

It's my understanding that the . t part of the code is a true/false signifier. But whether removing it from the file was wise or foolish, is what I want to know. Or, to state my question in the clearest of terms:

1. Did I successfully fix the problem? If not, why not?
2. Is there anything I should have done instead, or should do in addition to removing the (shell . t)?

Answer 1

Did you successfully fix the problem? Sure! ob-shell was flipping out and you stopped loading it. That is, in some sense, a fix!

That said: the chunk of code you found and commented out controls which languages are loaded by org babel, which is a pretty powerful function within org. If you've got any interest in using/evaluating shell code blocks, you'll want to fix the error you got a different way. You're right -- . t associates truth with a value. In this case, it indicates that org should load the shell backend for org source blocks.

All this said: if you want the shell backend running, there isn't reeeeeally enough information in your original post to diagnose what's wrong with it. I can tell you my config file doesn't have (shell . t), but rather (sh . t). One thing to double-check is that you're using a version of Org Mode greater than 8, which you can do with M-x org-version. Beyond that, I've very little to suggest at time of writing.

So! Do you want to use shell source blocks? If yes: more problem solving ahead! If no: you fixed it!

Answer 2

I encountered the same problem. I got my fresh new Emacs 25.3 with a built-in org-mode of version 8.2.10. When I started Emacs with my old init file, I got the exactly same thing.

File error: Cannot open load file, no such file or directory, ob-shell

I googled the error message and found this question. Then I changed (shell . t) to (sh . t). It seemed to resolve the error message.

However, some days later, when I tried to really use org-mode, I found the built-in version lacking some feature and updated it to 9.1.4. Then I encountered the following error when reallying executing something in org-mode.

Symbol’s function definition is void: org-babel-get-header

Then I changed (sh . t) back to (shell . t) and resolved the problem.

It seemed to me that the name of ob-sh was changed from ob-sh to ob-shell somewhere between version 8.2.10 and 9.1.4.