blog.3-json: init

site/blog/2025-07-21-3-json.md

@@ -0,0 +1,60 @@
+---
+title: 3-json
+description: tree, not three
+
+tags:
+- cli
+---
+
+From the
+[`tree(1)` release notes](https://oldmanprogrammer.net/source.php?dir=projects/tree/CHANGES),
+version 2.0.0:
+
+> - Output un-indented JSON on file descriptor 3 ("stddata") automatically if
+>   file descriptor 3 is present (currently Linux only.) Maybe switch to BSON.
+
+Surely, nothing will happen if I just assume that the existence of a specific
+file descriptor implies something, as nobody is crazy or stupid enough to
+hardcode such a thing? **_\<insert sounds of cars crashing in the
+background\>_**
+
+Oops (from the `tree`version 2.0.2 release notes):
+
+> - Okay, apparently the stddata addition is causing havoc (who knew how many
+>   scripts just haphazardly hand programs random file descriptors, that's
+>   surely not a problem.) Going forward the stddata option will only work if
+>   the environment variable STDDATA_FD is present or set to the descriptor to
+>   produce the JSON output on.
+
+Unix is a mess. But it's still cool we can have `tree` output structured data
+using `STDDATA_FD`:
+
+```json
+> STDDATA_FD=1 tree
+
+[{"type":"directory","name":".","contents":[{"type":"file","name":"2024-01-01-test.md"},{"type":"file","name":"2024-03-04-htmnix.md"},{"type":"file","name":"2024-04-02-cosmic-drift.md"},{"type":"file","name":"2024-04-15-nix-iceberg.md"},{"type":"file","name":"2024-05-20-swap-i.md"},{"type":"file","name":"2024-09-30-gitignore.md"},{"type":"file","name":"2025-06-05-why-cores.md"},{"type":"file","name":"2025-06-09-nginix.md"},{"type":"file","name":"2025-06-20-intro-cab.md"},{"type":"file","name":"2025-07-04-derive-broken.md"},{"type":"file","name":"2025-07-20-no-gnulib.md"},{"type":"file","name":"_data.ts"}]},{"type":"report","directories":1,"files":12}]
+```
+
+Also, obligatory [nushell](https://nushell.sh/) mention (using the `markdown`
+table style because for some reason the fancy characters don't render properly
+with my webfont):
+
+```sh
+> STDDATA_FD=1 tree | from json
+
+|-#-|---type----|-name-|------------------contents-------------------|-directories-|-files-|
+| 0 | directory | .    | |-#--|-type-|------------name-------------| |    nope     | nope  |
+|   |           |      | |  0 | file | 2024-01-01-test.md          | |             |       |
+|   |           |      | |  1 | file | 2024-03-04-htmnix.md        | |             |       |
+|   |           |      | |  2 | file | 2024-04-02-cosmic-drift.md  | |             |       |
+|   |           |      | |  3 | file | 2024-04-15-nix-iceberg.md   | |             |       |
+|   |           |      | |  4 | file | 2024-05-20-swap-i.md        | |             |       |
+|   |           |      | |  5 | file | 2024-09-30-gitignore.md     | |             |       |
+|   |           |      | |  6 | file | 2025-06-05-why-cores.md     | |             |       |
+|   |           |      | |  7 | file | 2025-06-09-nginix.md        | |             |       |
+|   |           |      | |  8 | file | 2025-06-20-intro-cab.md     | |             |       |
+|   |           |      | |  9 | file | 2025-07-04-derive-broken.md | |             |       |
+|   |           |      | | 10 | file | 2025-07-20-no-gnulib.md     | |             |       |
+|   |           |      | | 11 | file | _data.ts                    | |             |       |
+| 1 | report    | nope |                    nope                     |           1 |    12 |
+```