diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f1b3b31e4d..ba227ab62b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2018-03-14  Tom Tromey  <tom@tromey.com>
+
+	* printcmd.c (_initialize_printcmd): Add usage to printf.
+
 2018-03-14  Yao Qi  <qiyao@sourceware.org>
 
 	* MAINTAINERS: Update my email address.
diff --git a/gdb/printcmd.c b/gdb/printcmd.c
index fc9d7e4dd9..13b967f0a2 100644
--- a/gdb/printcmd.c
+++ b/gdb/printcmd.c
@@ -2680,8 +2680,9 @@ No argument means cancel all automatic-display expressions.\n\
 Do \"info display\" to see current list of code numbers."), &deletelist);
 
   add_com ("printf", class_vars, printf_command, _("\
-printf \"printf format string\", arg1, arg2, arg3, ..., argn\n\
-This is useful for formatted output in user-defined commands."));
+Formatted printing, like the C \"printf\" function.\n\
+Usage: printf \"format string\", arg1, arg2, arg3, ..., argn\n\
+This supports most C printf format specifications, like %s, %d, etc."));
 
   add_com ("output", class_vars, output_command, _("\
 Like \"print\" but don't put in value history and don't print newline.\n\