Update HAB_STUDIO_BINARY testing changes section
@@ -85,6 +85,17 @@ or setting the value upon execution of the `hab` binary:
env HAB_SUP_BINARY=/path/to/habitat/target/debug/hab-sup hab sup status
```
+## HAB_STUDIO_BINARY
+
+This one is a bit special. Technically [hab-studio.sh](https://github.com/habitat-sh/habitat/blob/master/components/studio/bin/hab-studio.sh) is a shell script file and not binary. This also means that there is no need to build anything; set `HAB_STUDIO_BINARY` to the path to a version of `hab-studio.sh` within a `habitat` checkout and it will be used. This override will also affect which versions of the files in [studio/libexec](https://github.com/habitat-sh/habitat/tree/master/components/studio/libexec) are used. So if you want to test out changes to [hab-studio-profile.sh](https://github.com/habitat-sh/habitat/blob/master/components/studio/libexec/hab-studio-profile.sh) or [hab-studio-type-default.sh](https://github.com/habitat-sh/habitat/blob/master/components/studio/libexec/hab-studio-type-default.sh), make those changes in a checkout of the `habitat` repo located at `/path/to/habitat/repo` and set `HAB_STUDIO_BINARY` to `/path/to/habitat/repo/components/studio/bin/hab-studio.sh`. For example:
+```bash
+$ env HAB_STUDIO_BINARY=/path/to/habitat/repo/components/studio/bin/hab-studio.sh hab studio enter
+```
+Once inside the studio, the prompt will indicate that the override is in effect:
+```bash
+[1][HAB_STUDIO_BINARY][default:/src:0]#
+```
+
# Unsupported environments
## Mac OS X for Linux Development
