feat(shell): add startup_command run in each new pane

CHANGELOG.md

@@ -6,6 +6,7 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 ## [Unreleased]
 
 ### Added
+- add `shell.startup_command` to run a command in each new pane
 - add `--maximized` and `--fullscreen` flags to start the window in that mode
 - persist and restore window size, maximized, and fullscreen state per session
 - REP (`CSI Ps b`): repeat the last printed character `Ps` times

README.md

@@ -162,6 +162,7 @@ cursor_blink_ms = 500
 
 [shell]
 # program = "/bin/zsh"   # defaults to $SHELL
+# startup_command = "ssh myserver"   # run in each new pane (not on session restore)
 
 [terminal]
 scrollback_lines = 10000  # minimum 100

assets/config.toml

@@ -14,6 +14,7 @@ detect_urls     = true
 
 [shell]
 # program = "/bin/zsh"
+# startup_command = "ssh myserver"
 
 [terminal]
 scrollback_lines = 10000

doc/SPEC.md

@@ -223,11 +223,16 @@ Screenshot capture is a two-step flow: region selection followed by a name promp
 | window | detect_urls | bool | `true` |
 | terminal | scrollback_lines | uint | `10000` (min 100) |
 | shell | program | string? | `$SHELL` |
+| shell | startup_command | string? | `none` |
 | logging | auto_log | bool | `false` |
 | logging | log_dir | string | `""` (→ `~/.mmterm`) |
 | status_bar | right | string | `""` |
 | theme | name | string | `"default"` |
 
+`shell.startup_command`, when set, is written to every newly spawned interactive
+pane (new tab or split) right after the shell starts. It is **not** re-run for
+panes restored from a saved session.
+
 ### Themes
 
 Themes define all terminal and UI colors in a single `.toml` file.

src/config/config_test.rs

@@ -283,3 +283,39 @@ fn general_update_defaults() {
     assert!(cfg.general.shell_integration); // OSC 133 prompt/exit badges on by default
     assert!(cfg.general.desktop_notifications); // OSC 777 desktop notifications on by default
 }
+
+#[test]
+fn startup_command_defaults_to_none_when_missing() {
+    let toml = r###"
+[font]
+family = "Mono"
+size = 14.0
+[window]
+width = 800
+height = 600
+title = "t"
+cursor_blink_ms = 500
+[shell]
+program = "/bin/zsh"
+[colors]
+background = "#000000"
+foreground = "#ffffff"
+cursor = "#ffffff"
+selection = "#333333"
+palette = []
+"###;
+    let cfg: Config = toml::from_str(toml).expect("parse failed");
+    assert!(cfg.shell.startup_command.is_none());
+}
+
+#[test]
+fn startup_command_round_trips() {
+    let mut cfg = Config::default();
+    cfg.shell.startup_command = Some("ssh myserver".to_string());
+    let serialized = toml::to_string_pretty(&cfg).expect("serialize failed");
+    let parsed: Config = toml::from_str(&serialized).expect("parse failed");
+    assert_eq!(
+        parsed.shell.startup_command,
+        Some("ssh myserver".to_string())
+    );
+}

src/config/mod.rs

@@ -163,6 +163,8 @@ pub struct WindowConfig {
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct ShellConfig {
     pub program: Option<String>,
+    #[serde(default)]
+    pub startup_command: Option<String>,
 }
 
 fn default_auto_log() -> bool {

src/config/tui_config.rs

@@ -33,6 +33,7 @@ const F_AUTO_UPDATE_CHECK: usize = 37;
 const F_AUTO_UPDATE_INSTALL: usize = 38;
 const F_SHELL_INTEGRATION: usize = 39;
 const F_DESKTOP_NOTIFICATIONS: usize = 40;
+const F_STARTUP_COMMAND: usize = 41;
 
 const PALETTE_LABELS: [&str; 16] = [
     "Palette 0  black",
@@ -301,6 +302,13 @@ impl ConfigPanel {
             kind: FieldKind::Bool,
             section: None,
         });
+        fields.push(Field {
+            label: "Startup Command",
+            hint: "command run in each new pane (empty = none)",
+            value: cfg.shell.startup_command.clone().unwrap_or_default(),
+            kind: FieldKind::OptText,
+            section: None,
+        });
 
         let mut collapsed = HashSet::new();
         collapsed.insert("Palette");
@@ -628,6 +636,10 @@ impl ConfigPanel {
             let s = get(F_SHELL);
             if s.is_empty() { None } else { Some(s) }
         };
+        let startup_command = {
+            let s = get(F_STARTUP_COMMAND);
+            if s.is_empty() { None } else { Some(s) }
+        };
 
         let scrollback_lines = get(F_SCROLLBACK)
             .parse::<usize>()
@@ -688,7 +700,10 @@ impl ConfigPanel {
                 inactive_dim,
                 detect_urls,
             },
-            shell: ShellConfig { program: shell },
+            shell: ShellConfig {
+                program: shell,
+                startup_command,
+            },
             terminal: TerminalConfig { scrollback_lines },
             logging: LogConfig { auto_log, log_dir },
             colors: ColorsConfig {

src/config/tui_config_test.rs

@@ -10,8 +10,8 @@ fn make_panel() -> ConfigPanel {
 #[test]
 fn from_config_has_correct_field_count() {
     let panel = make_panel();
-    // 9 base + 1 scrollback + 2 logging + 1 theme + 4 colors + 16 palette + 1 status_bar + 3 general + 2 updates + 2 shell/notify = 41
-    assert_eq!(panel.fields.len(), 41);
+    // 9 base + 1 scrollback + 2 logging + 1 theme + 4 colors + 16 palette + 1 status_bar + 3 general + 2 updates + 2 shell/notify + 1 startup_command = 42
+    assert_eq!(panel.fields.len(), 42);
 }
 
 #[test]
@@ -308,6 +308,7 @@ fn distinct_config() -> Config {
         },
         shell: ShellConfig {
             program: Some("/bin/xyzsh".into()),
+            startup_command: None,
         },
         terminal: TerminalConfig {
             scrollback_lines: 4097,
@@ -375,6 +376,7 @@ fn field_index_sanity() {
         F_AUTO_UPDATE_INSTALL,
         F_SHELL_INTEGRATION,
         F_DESKTOP_NOTIFICATIONS,
+        F_STARTUP_COMMAND,
     ];
     occupied.extend((0..16).map(|i| F_PALETTE + i));
     occupied.sort_unstable();
@@ -455,6 +457,28 @@ fn build_config_shell_nonempty_becomes_some() {
     }
 }
 
+#[test]
+fn build_config_startup_command_empty_becomes_none() {
+    let mut panel = make_panel();
+    panel.fields[F_STARTUP_COMMAND].value = String::new();
+    if let ConfigAction::Save(cfg) = panel.save() {
+        assert!(cfg.shell.startup_command.is_none());
+    } else {
+        panic!("expected Save action");
+    }
+}
+
+#[test]
+fn build_config_startup_command_nonempty_becomes_some() {
+    let mut panel = make_panel();
+    panel.fields[F_STARTUP_COMMAND].value = "ssh myserver".to_string();
+    if let ConfigAction::Save(cfg) = panel.save() {
+        assert_eq!(cfg.shell.startup_command, Some("ssh myserver".to_string()));
+    } else {
+        panic!("expected Save action");
+    }
+}
+
 // ── Validation helpers ────────────────────────────────────────────────────────
 
 #[test]
@@ -680,8 +704,8 @@ fn palette_collapsed_by_default() {
 #[test]
 fn visible_indices_hides_palette_body() {
     let panel = make_panel();
-    // 41 total - 15 palette body fields = 26 visible
-    assert_eq!(panel.visible_indices().len(), 26);
+    // 42 total - 15 palette body fields = 27 visible
+    assert_eq!(panel.visible_indices().len(), 27);
 }
 
 #[test]
@@ -690,7 +714,7 @@ fn toggle_on_palette_header_expands() {
     panel.selected = F_PALETTE;
     panel.toggle_collapse();
     assert!(!panel.collapsed.contains("Palette"));
-    assert_eq!(panel.visible_indices().len(), 41);
+    assert_eq!(panel.visible_indices().len(), 42);
 }
 
 #[test]
@@ -700,7 +724,7 @@ fn toggle_twice_restores_collapsed() {
     panel.toggle_collapse();
     panel.toggle_collapse();
     assert!(panel.collapsed.contains("Palette"));
-    assert_eq!(panel.visible_indices().len(), 26);
+    assert_eq!(panel.visible_indices().len(), 27);
 }
 
 #[test]
@@ -755,10 +779,10 @@ fn move_up_skips_collapsed_palette() {
 #[test]
 fn move_down_at_last_visible_clamps() {
     let mut panel = make_panel();
-    // F_DESKTOP_NOTIFICATIONS is the last field and is always visible
-    panel.selected = F_DESKTOP_NOTIFICATIONS;
+    // F_STARTUP_COMMAND is the last field and is always visible
+    panel.selected = F_STARTUP_COMMAND;
     panel.handle_down();
-    assert_eq!(panel.selected, F_DESKTOP_NOTIFICATIONS);
+    assert_eq!(panel.selected, F_STARTUP_COMMAND);
 }
 
 #[test]

src/pane_ops.rs

@@ -24,6 +24,7 @@ impl App {
         tab_idx: usize,
         rect: [u32; 4],
         cwd: Option<std::path::PathBuf>,
+        run_startup: bool,
     ) -> Option<usize> {
         let id = self.state.next_pane_id;
         self.state.next_pane_id += 1;
@@ -109,6 +110,17 @@ impl App {
                         metrics,
                     },
                 );
+                // Run the configured startup command only for interactive new
+                // panes (new tab / split), never for panes restored from a
+                // saved session — restore callers pass `run_startup = false`.
+                if run_startup
+                    && let Some(cmd) = self.state.config.shell.startup_command.as_deref()
+                    && !cmd.is_empty()
+                    && let Some(entry) = self.state.tabs[tab_idx].panes.get_mut(&id)
+                    && let Err(e) = entry.pty.write_input(format!("{cmd}\n").as_bytes())
+                {
+                    log::warn!("Failed to write startup command to pane {id}: {e}");
+                }
                 Some(id)
             }
             Err(e) => {
@@ -125,7 +137,7 @@ impl App {
             .get(self.state.active_tab)
             .and_then(|t| t.panes.get(&t.active))
             .and_then(|e| e.pty.cwd());
-        self.spawn_pane_into(self.state.active_tab, rect, cwd)
+        self.spawn_pane_into(self.state.active_tab, rect, cwd, true)
     }
 
     pub(crate) fn new_tab(&mut self, win_w: u32, win_h: u32) {
@@ -157,7 +169,7 @@ impl App {
             passthrough: false,
             mode: InputMode::Insert,
         });
-        match self.spawn_pane_into(tab_idx, initial_rect, cwd) {
+        match self.spawn_pane_into(tab_idx, initial_rect, cwd, true) {
             Some(id) => {
                 self.state.tabs[tab_idx].layout = Layout::new(id, win_w, win_h);
                 self.state.tabs[tab_idx].active = id;

src/restore.rs

@@ -102,7 +102,7 @@ impl App {
                     } else {
                         Some(home.clone())
                     };
-                    self.spawn_pane_into(tab_idx, rect, cwd_opt)
+                    self.spawn_pane_into(tab_idx, rect, cwd_opt, false)
                 })
                 .collect();
             if !self.restore_tab_layout(tab_idx, tab_sess, &slot_to_id, rect, win_w, win_h) {
@@ -176,7 +176,7 @@ impl App {
         // No saved pane spawned (empty tab, or every spawn failed): try one fresh
         // fallback pane; if even that fails, drop the empty tab so we never leave a
         // ghost tab with no panes.
-        match self.spawn_pane_into(tab_idx, rect, None) {
+        match self.spawn_pane_into(tab_idx, rect, None, false) {
             Some(id) => {
                 self.state.tabs[tab_idx].layout = Layout::new(id, win_w, win_h);
                 self.state.tabs[tab_idx].active = id;