diff --git a/src/helper/command.c b/src/helper/command.c
index a82eb4dae5cdfca911c3a8bb2a744cd5d87ae9d5..bda5182053fc8364c7de28ad2b2ad23905e9eb0b 100644
--- a/src/helper/command.c
+++ b/src/helper/command.c
@@ -337,7 +337,7 @@ void command_output_text(command_context_t *context, const char *data)
 	}
 }
 
-void command_print_n(command_context_t *context, char *format, ...)
+void command_print_sameline(command_context_t *context, const char *format, ...)
 {
 	char *string;
 
@@ -361,7 +361,7 @@ void command_print_n(command_context_t *context, char *format, ...)
 	va_end(ap);
 }
 
-void command_print(command_context_t *context, char *format, ...)
+void command_print(command_context_t *context, const char *format, ...)
 {
 	char *string;
 
@@ -497,7 +497,7 @@ int command_run_line(command_context_t *context, char *line)
 	return retval;
 }
 
-int command_run_linef(command_context_t *context, char *format, ...)
+int command_run_linef(command_context_t *context, const char *format, ...)
 {
 	int retval=ERROR_FAIL;
 	char *string;
diff --git a/src/helper/command.h b/src/helper/command.h
index df3d37a52abba69d4d22b2ccceb38ad7179f9a50..75e513d84624ea27ec48f2f47df6895302c841e8 100644
--- a/src/helper/command.h
+++ b/src/helper/command.h
@@ -84,12 +84,12 @@ extern int command_context_mode(command_context_t *context, enum command_mode mo
 extern command_context_t* command_init(void);
 extern int command_done(command_context_t *context);
 
-extern void command_print(command_context_t *context, char *format, ...)
+extern void command_print(command_context_t *context, const char *format, ...)
 		__attribute__ ((format (printf, 2, 3)));
-extern void command_print_sameline(command_context_t *context, char *format, ...)
+extern void command_print_sameline(command_context_t *context, const char *format, ...)
 		__attribute__ ((format (printf, 2, 3)));
 extern int command_run_line(command_context_t *context, char *line);
-extern int command_run_linef(command_context_t *context, char *format, ...)
+extern int command_run_linef(command_context_t *context, const char *format, ...)
 		__attribute__ ((format (printf, 2, 3)));
 extern void command_output_text(command_context_t *context, const char *data);