Add an option to override the default shell

kitty/kitty.conf

@@ -104,6 +104,10 @@ click_interval 0.5
 # database will be matched.
 select_by_word_characters :@-./_~?&=%+#
 
+# The shell program to execute. The default value of . means
+# to use whatever shell is set as the default shell for the current user.
+shell .
+
 # Hide mouse cursor after the specified number of seconds of the mouse not being used. Set to
 # zero to disable mouse cursor hiding.
 mouse_hide_wait 3.0

kitty/session.py

@@ -64,6 +64,15 @@ class Session:
         self.tabs[-1].cwd = val
 
 
+def resolved_shell(opts):
+    ans = opts.shell
+    if ans == '.':
+        ans = [shell_path]
+    else:
+        ans = shlex.split(ans)
+    return ans
+
+
 def parse_session(raw, opts):
     ans = Session()
     ans.add_tab(opts)
@@ -90,7 +99,7 @@ def parse_session(raw, opts):
                 raise ValueError('Unknown command in session file: {}'.format(cmd))
     for t in ans.tabs:
         if not t.windows:
-            t.windows.append([shell_path])
+            t.windows.append(resolved_shell(opts))
     return ans
 
 
@@ -108,7 +117,7 @@ def create_session(opts, args=None, special_window=None, cwd_from=None):
     ans.add_tab(opts)
     ans.tabs[-1].layout = current_layout
     if special_window is None:
-        cmd = args.args if args and args.args else [shell_path]
+        cmd = args.args if args and args.args else resolved_shell(opts)
         from kitty.tabs import SpecialWindow
         k = {'cwd_from': cwd_from}
         if getattr(args, 'title', None):

kitty/tabs.py

@@ -9,15 +9,14 @@ from functools import partial
 from .borders import Borders
 from .child import Child
 from .config import build_ansi_color_table
-from .constants import (
-    WindowGeometry, appname, get_boss, is_macos, is_wayland, shell_path
-)
+from .constants import WindowGeometry, appname, get_boss, is_macos, is_wayland
 from .fast_data_types import (
     DECAWM, Screen, add_tab, glfw_post_empty_event, remove_tab, remove_window,
     set_active_tab, set_active_window, set_tab_bar_render_data, swap_tabs,
     swap_windows, viewport_for_window, x11_window_id
 )
 from .layout import Rect, all_layouts
+from .session import resolved_shell
 from .utils import color_as_int
 from .window import Window, calculate_gl_geometry
 
@@ -118,9 +117,9 @@ class Tab:  # {{{
     def launch_child(self, use_shell=False, cmd=None, stdin=None, cwd_from=None, cwd=None):
         if cmd is None:
             if use_shell:
-                cmd = [shell_path]
+                cmd = resolved_shell(self.opts)
             else:
-                cmd = self.args.args or [shell_path]
+                cmd = self.args.args or resolved_shell(self.opts)
         env = {}
         if not is_macos and not is_wayland:
             try: