diff --git a/install.py b/install.py
index d542682..aef7bed 100755
--- a/install.py
+++ b/install.py
@@ -258,24 +258,31 @@ class Installer:
 
         src_full.symlink(p_dest)
 
-    def do_append(self, dest: str, content: str) -> None:
+    def do_append(self, dest: str, content: str, condition: str = "true") -> None:
         """Append to a file."""
 
-        self._do_write(dest, content, append=True)
+        self._do_write(dest, content, condition=condition, append=True)
 
-    def do_write(self, dest: str, content: str) -> None:
+    def do_write(self, dest: str, content: str, condition: str = "true") -> None:
         """Write into a file."""
 
-        self._do_write(dest, content, append=False)
+        self._do_write(dest, content, condition=condition, append=False)
 
-    def _do_write(self, dest: str, content: str, *, append: bool) -> None:
+    def _do_write(
+        self, dest: str, content: str, *, condition: str, append: bool
+    ) -> None:
         p_dest = Path(dest).expanduser()
         pretty_dest = self.pretty_path(p_dest)
 
-        if p_dest.exists() and not self.force and not append:
+        if not self.evaluate_condition(condition):
             ui.info_2("Skipping", pretty_dest)
             return
 
+        if p_dest.exists() and not self.force and not append:
+            if not ui.ask_yes_no(f"{pretty_dest} already exists. Overwrite?"):
+                ui.info_2("Skipping", pretty_dest)
+                return
+
         ui.info_2("Creating", pretty_dest)
         p_dest.parent.makedirs_p()
         content = content.format(base_dir=self.base_dir, home=self.home)