# Tutorial: debug language installation Except for the simplest cases, it's often helpful to debug lanugage installation interactively. Open a new tab in the admin shell (`control-b c`) and start the packaging image: ``` $ make shell I=packaging ``` You'll probably want another instance of tmux: ``` $ make tmux ``` Now you should have at least three tabs in the top-level tmux: one with the admin shell, one with the runtime shell, and one with the packaging shell. ## Targeted debugging commands Switch to the packaging shell and delete any leftover artifacts from the previous build: ``` $ make pkg-clean T=lang L=mylanguage ``` Then start a shell in the same context as the `install` scripts would be run. ``` $ make pkg-debug T=lang L=mylanguage ``` Now you can run installation commands manually to make sure they're working. Normally the generated build script will be run; you can see it by running ``` $ make script T=lang L=mylanguage ``` and checking `build/lang//build.bash`. You can also run that script in the appropriate context before entering your `pkg-debug` session: ``` $ make pkg-build T=lang L=mylanguage ``` After you're satisfied with the layout of files you've put into `${pkg}` and want to try installing the resulting package, start by building the `.deb`: ``` $ make pkg-deb T=lang L=mylanguage ``` Then switch to the runtime shell. If you still only have one tab open inside the nested tmux session, open a new one (`control-b control-b c`). You can install the `.deb`: ``` $ make install T=lang L=mylanguage ``` At this point your language should be runnable so you can test it out. It's best to test inside an isolated sandbox with the same set of environment variables as will appear on Riju, though; you can start such a shell as follows: ``` $ make sandbox L=mylanguage ``` You may find that the language fails to run as expected due to packaging errors. If so, you can return to the packaging shell and make adjustments inside `pkg-debug` before rebuilding and reinstalling the package.