Add context command

README.md

@@ -39,6 +39,7 @@ contain a `dirs.toml` file that specifies a different location.
 
 Files ending with `.tmpl` are treated as [handlebars templates](https://handlebarsjs.com/) and are processed
 before being written to the target location. The `.tmpl` extension will be stripped from the filename.
+You can check the available context variables and their values on the system with `silo context`.
 
 
 ### Applying the configuration

src/args.rs

@@ -20,4 +20,7 @@ pub enum Command {
     Init,
     /// Applies the configuration stored in a silo repo
     Apply,
+
+    /// Print the entire context available to templates
+    Context,
 }

src/main.rs

@@ -16,6 +16,12 @@ fn main() -> Result<()> {
     match &args.command {
         args::Command::Init => init(&args)?,
         args::Command::Apply => apply(&args)?,
+        args::Command::Context => {
+            println!(
+                "{}",
+                serde_json::to_string_pretty(templating::context()).into_diagnostic()?
+            )
+        }
     }
 
     Ok(())