Add See Where asdf Gets Current Tool Version as a Unix TIL

unix/see-where-asdf-gets-current-tool-version.md

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+# See Where asdf Gets Current Tool Version
+
+The other day I [installed the latest version of
+Ruby](ruby/install-latest-version-of-ruby-with-asdf.md) with `asdf`. I then set
+that version (`3.4.1`) as the global default. However, when I then ran `ruby
+--version`, I was getting a `3.2.x` version. I checked my current project's
+directory and there was no `.tool-versions` file, so it wasn't being set by my
+current directory.
+
+`asdf` looks up the current chain of directories until it encounters a
+`.tool-versions` file, so it must have been finding one somewhere up there, but
+before it was getting to the _global_ `.tool-versions` file. But where?
+
+The `asdf current` command can tell us for a specific tool what the current
+version it is set to and what file is giving that directive.
+
+```bash
+asdf current ruby
+ruby            3.2.2           /Users/jbranchaud/code/.tool-versions
+```
+
+As it turns out, I had a `.tool-versions` file in `$HOME/code` that was setting
+that `3.2.x` Ruby version.
+
+I didn't want that directory controlling the Ruby version, so I removed `ruby`
+from that file. `asdf` was then able to traverse up to `$HOME/.tool-versions`
+for the global setting.
+
+See `asdf help` for more details.