diff --git a/phpdbg.h b/phpdbg.h
index 26fb118f4a4..f34fa4c84e0 100644
--- a/phpdbg.h
+++ b/phpdbg.h
@@ -22,6 +22,7 @@
 #include "zend_ini_scanner.h"
 #include "zend_globals.h"
 #include "zend_stream.h"
+#include "zend_builtin_functions.h"
 #include "SAPI.h"
 #include <php_config.h>
 #include "php_main.h"
diff --git a/phpdbg_help.c b/phpdbg_help.c
index 4edc20bb55d..b3467a4eaae 100644
--- a/phpdbg_help.c
+++ b/phpdbg_help.c
@@ -96,3 +96,11 @@ PHPDBG_HELP(cont) /* {{{ */
     printf("[Warnings about using stepping and break points here]\n");
     return SUCCESS;
 } /* }}} */
+
+PHPDBG_HELP(back) { /* {{{ */
+    printf("The backtrace is gathered with the default debug_backtrace functionality.\n");
+    printf("You can set the limit on the trace, for example:\n");
+    printf("phpdbg> back 5\n");
+    printf("Will limit the number of frames to 5, the default is no limit\n");
+    return SUCCESS;
+} /* }}} */
diff --git a/phpdbg_help.h b/phpdbg_help.h
index ca510b942a5..597dfdca866 100644
--- a/phpdbg_help.h
+++ b/phpdbg_help.h
@@ -40,6 +40,7 @@ PHPDBG_HELP(eval);
 PHPDBG_HELP(print);
 PHPDBG_HELP(break);
 PHPDBG_HELP(cont);
+PHPDBG_HELP(back);
 
 /**
  * Commands
@@ -54,6 +55,7 @@ static const phpdbg_command_t phpdbg_help_commands[] = {
   PHPDBG_HELP_D(print,    "printing allows inspection of the execution environment"),
   PHPDBG_HELP_D(break,    "breakpoints allow execution interruption"),
   PHPDBG_HELP_D(cont,     "use continue when a break point is met"),
+  PHPDBG_HELP_D(back,     "show debug backtrace information during execution"),
   {NULL, 0, 0}
 };