diff --git a/tools/lint/cmd.h b/tools/lint/cmd.h
index 9f6f88d..071348f 100644
--- a/tools/lint/cmd.h
+++ b/tools/lint/cmd.h
@@ -27,6 +27,7 @@
     void (*func)(struct ly_ctx **ctx, const char *); /* Function to call to do the command. */
     void (*help_func)(void);                         /* Display command help. */
     char *helpstring;                                /* Documentation for this function. */
+    char *optstring;                                 /* Option characters used in function getopt_long. */
 } COMMAND;
 
 /**
@@ -34,6 +35,25 @@
  */
 extern COMMAND commands[];
 
+/**
+ * @brief Index for global variable ::commands.
+ */
+enum COMMAND_INDEX {
+    CMD_HELP = 0,
+    CMD_ADD,
+    CMD_LOAD,
+    CMD_PRINT,
+    CMD_DATA,
+    CMD_LIST,
+    CMD_FEATURE,
+    CMD_SEARCHPATH,
+    CMD_CLEAR,
+    CMD_VERB,
+#ifndef NDEBUG
+    CMD_DEBUG,
+#endif
+};
+
 /* cmd_add.c */
 void cmd_add(struct ly_ctx **ctx, const char *cmdline);
 void cmd_add_help(void);