2 files changed, 20 insertions, 9 deletions
diff --git a/src/user/knob/file.c b/src/user/knob/file.c
index 8ab7acd..0032cf2 100644
--- a/src/user/knob/file.c
+++ b/src/user/knob/file.c
@@ -9,9 +9,9 @@ struct file {
   uint32_t length;
 };
 
-static const char *try_remove_prefix(const char *path, uint8_t *dn_out) {
+const char *remove_prefix(const char *path, uint8_t *dn_out) {
   if ((path[0] != 's') || (path[1] != 'd'))
-    return 0;
+    goto no_prefix;
 
   const char *num_part = path + 2;
   for (uint32_t i = 0; num_part[i]; ++i)
@@ -19,22 +19,20 @@ static const char *try_remove_prefix(const char *path, uint8_t *dn_out) {
 
       uint32_t dn_large;
       if (!try_sntoi(num_part, i, &dn_large) || dn_large > 255)
-        return 0;
+        goto no_prefix;
 
       *dn_out = (uint8_t)dn_large;
       return num_part + i + 1;
     }
 
-  return 0;
+no_prefix:
+  *dn_out = current_drive;
+  return path;
 }
 
 struct file *open_file(const char *path) {
   uint8_t dn;
-  const char *path_part = try_remove_prefix(path, &dn);
-  if (path_part)
-    path = path_part;
-  else
-    dn = current_drive;
+  path = remove_prefix(path, &dn);
 
   _file_handle_t h = _open_file(dn, path);
   if (!h)
diff --git a/src/user/knob/task.c b/src/user/knob/task.c
new file mode 100644
index 0000000..aa18eab
--- /dev/null
+++ b/src/user/knob/task.c
@@ -0,0 +1,13 @@
+#include <stdbool.h>
+#include <pland/syscall.h>
+#include <knob/file.h>
+
+bool try_run_command(const char *path) {
+  uint8_t dn;
+  path = remove_prefix(path, &dn);
+  return _start_task(dn, path);
+}
+
+void yield_task() {
+  _yield_task();
+}
+\ No newline at end of file