[Solved] .rbenv/shims/ruby: Argument list too long

I couldn't access any ruby command in the linux server where we have hosted the Rails app for one of my client. I had to access rails console to update some database records manually but I couldn't and got stuck in this issue for over 2 days.

I encountered two issues along the way:

ruby version not found
.rbenv/shims/ruby: Argument list too long

Solving the second issue solved the first issue too!

Problem

Inside the root folder of the project , ruby -v always returned that ruby 2.7.0 was not found and need to be installed. When I tried installing ruby 2.7.0 via rbenv, it said version already exists.

I tried to execute ruby -v outside of the project just to be sure that it was not a problem with ruby version. It took a really long time to process the command which returned with following error:

/home/deploy/.rbenv/libexec/rbenv-exec: line 47: /home/deploy/.rbenv/shims/ruby: Argument list too long

Google searches didn't yield any relevant results.

In the process (after searching more for around two days), I stumbled upon the rbenv issue rbenv: cannot rehash. I had never imagined these issues to be related at all. I executed the command to rehash the rbenv to see if it executes successfully instead of throwing the error mentioned in the Github issue.

Boom! same issue; rbenv could not be rehashed.

Solution as mentioned in the replies was to delete the file ".rbenv-shim", and rehash rbenv again. It worked!

Solution

Execute the command rbenv rehash. It will return the location of the file you have to delete:

rbenv: cannot rehash: /home/deploy/.rbenv/shims/.rbenv-shim exists

Here, "/home/deploy/.rbenv/shims/.rbenv-shim" is the location of the file in my machine and it could be different in your local machine.

Remove the file to resolve the issue:

rm /home/deploy/.rbenv/shims/.rbenv-shim

Now when you run the command ruby -v it will return the version of ruby currently installed in your machine.

Reason behind the issue

It happens when previous rehash of the rbenv was killed prematurely.

Quoting from reply to the Github Issue:

During the rehash process, rbenv writes out the temporary file .rbenv-shim to indicate that the rehash is in progress. Then, if a parallel rbenv rehash process tries to run at the same time, it will fail because the file already exists. This guards against race conditions in parallel rehashes.

It seems like .rbenv-shim file was never cleaned up after a rehash that ran earlier. That earlier process might have been killed prematurely and never cleaned up after itself.

Conclusion

I am not sure if solution to the issue .rbenv/shims/ruby: Argument list too long is always to delete the ".rbenv-shim" file but hey, it's worth a try.

If the solution to your problem was different than this, please let us know below in the replies and I will be sure to include it in this blog so that it helps others.

Thank you for reading. Happy coding!