add history session command (#6587)

crates/nu-command/src/misc/history_session.rs

@@ -0,0 +1,43 @@
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::{Category, Example, IntoPipelineData, PipelineData, Signature, Value};
+
+#[derive(Clone)]
+pub struct HistorySession;
+
+impl Command for HistorySession {
+    fn name(&self) -> &str {
+        "history session"
+    }
+
+    fn usage(&self) -> &str {
+        "Get the command history session"
+    }
+
+    fn signature(&self) -> nu_protocol::Signature {
+        Signature::build("history session").category(Category::Misc)
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            example: "history session",
+            description: "Get current history session",
+            result: None,
+        }]
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        _stack: &mut Stack,
+        call: &Call,
+        _input: PipelineData,
+    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
+        Ok(Value::Record {
+            cols: vec!["session-id".into()],
+            vals: vec![Value::int(engine_state.history_session_id, call.head)],
+            span: call.head,
+        }
+        .into_pipeline_data())
+    }
+}

crates/nu-command/src/misc/mod.rs

@@ -1,5 +1,7 @@
 mod history;
+mod history_session;
 mod tutor;
 
 pub use history::History;
+pub use history_session::HistorySession;
 pub use tutor::Tutor;