Add history command (#553)

crates/nu-command/src/core_commands/history.rs

@@ -0,0 +1,65 @@
+use nu_protocol::ast::Call;
+use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::{
+    Category, IntoInterruptiblePipelineData, PipelineData, ShellError, Signature, Value,
+};
+
+#[derive(Clone)]
+pub struct History;
+
+impl Command for History {
+    fn name(&self) -> &str {
+        "history"
+    }
+
+    fn usage(&self) -> &str {
+        "Get the command history"
+    }
+
+    fn signature(&self) -> nu_protocol::Signature {
+        Signature::build("history")
+            .switch("clear", "Clears out the history entries", Some('c'))
+            .category(Category::Core)
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        _stack: &mut Stack,
+        call: &Call,
+        _input: PipelineData,
+    ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
+        let head = call.head;
+        if let Some(config_path) = nu_path::config_dir() {
+            let clear = call.has_flag("clear");
+            let ctrlc = engine_state.ctrlc.clone();
+
+            let mut history_path = config_path;
+            history_path.push("nushell");
+            history_path.push("history.txt");
+
+            if clear {
+                let _ = std::fs::remove_file(history_path);
+                Ok(PipelineData::new(head))
+            } else {
+                let contents = std::fs::read_to_string(history_path);
+
+                if let Ok(contents) = contents {
+                    Ok(contents
+                        .lines()
+                        .map(move |x| Value::String {
+                            val: x.to_string(),
+                            span: head,
+                        })
+                        .collect::<Vec<_>>()
+                        .into_iter()
+                        .into_pipeline_data(ctrlc))
+                } else {
+                    Err(ShellError::FileNotFound(head))
+                }
+            }
+        } else {
+            Err(ShellError::FileNotFound(head))
+        }
+    }
+}

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

@@ -10,6 +10,7 @@ mod export_env;
 mod for_;
 mod help;
 mod hide;
+mod history;
 mod if_;
 mod let_;
 mod module;
@@ -29,6 +30,7 @@ pub use export_env::ExportEnv;
 pub use for_::For;
 pub use help::Help;
 pub use hide::Hide;
+pub use history::History;
 pub use if_::If;
 pub use let_::Let;
 pub use module::Module;

crates/nu-command/src/default_context.rs

@@ -35,6 +35,7 @@ pub fn create_default_context() -> EngineState {
             For,
             Help,
             Hide,
+            History,
             If,
             Let,
             Module,