From cd33acbd515e7b101982fa5bd10ba33ec01b5f37 Mon Sep 17 00:00:00 2001
From: pancake <pancake@nopcode.org>
Date: Wed, 14 Jun 2017 17:31:57 +0200
Subject: [PATCH] Implement !- and !-* commands to clear command history

---
 libr/cons/dietline.c | 8 ++++++--
 libr/core/cmd.c      | 8 ++++++++
 libr/core/file.c     | 2 ++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/libr/cons/dietline.c b/libr/cons/dietline.c
index f268fb1a87..a52d174d52 100644
--- a/libr/cons/dietline.c
+++ b/libr/cons/dietline.c
@@ -80,7 +80,7 @@ static int r_line_readchar_utf8(unsigned char *s, int slen) {
 		}
 		s[len] = r_cons_controlz (s[len]);
 		if (!s[len]) {
-			return 1;	// ^z
+			return 1; // ^z
 		}
 		if (s[len] < 28) {
 			return s[0]? 1: 0;
@@ -100,8 +100,9 @@ static int r_line_readchar_utf8(unsigned char *s, int slen) {
 	return len;
 }
 #endif
+
 #if __WINDOWS__ && !__CYGWIN__
-static int r_line_readchar_win(int *vch) {	// this function handle the input in console mode
+static int r_line_readchar_win(int *vch) { // this function handle the input in console mode
 	INPUT_RECORD irInBuf[128];
 	BOOL ret, bCtrl = FALSE;
 	DWORD mode, out;
@@ -351,6 +352,9 @@ R_API int r_line_hist_load(const char *file) {
 R_API int r_line_hist_save(const char *file) {
 	FILE *fd;
 	int i, ret = false;
+	if (!file || !*file) {
+		return false;
+	}
 	char *p, *path = r_str_home (file);
 	if (path != NULL) {
 		p = (char *) r_str_lastbut (path, R_SYS_DIR[0], NULL);	// TODO: use fs
diff --git a/libr/core/cmd.c b/libr/core/cmd.c
index 02e229711c..47bd8e055b 100644
--- a/libr/core/cmd.c
+++ b/libr/core/cmd.c
@@ -1135,6 +1135,14 @@ static int cmd_system(void *data, const char *input) {
 	ut64 n;
 	int ret = 0;
 	switch (*input) {
+	case '-':
+		if (input[1]) {
+			r_line_hist_free();
+			r_line_hist_save (R2_HOMEDIR"/history");
+		} else {
+			r_line_hist_free();
+		}
+		break;
 	case '=':
 		if (input[1] == '?') {
 			r_cons_printf ("Usage: !=[!]  - enable/disable remote commands\n");
diff --git a/libr/core/file.c b/libr/core/file.c
index 611c0e8bc2..b3b98701d9 100644
--- a/libr/core/file.c
+++ b/libr/core/file.c
@@ -184,6 +184,8 @@ R_API void r_core_sysenv_help(const RCore *core) {
 		"!!", "ls~txt", "print output of 'ls' and grep for 'txt'",
 		".!", "rabin2 -rpsei ${FILE}", "run each output line as a r2 cmd",
 		"!", "echo $SIZE", "display file size",
+		"!-", "", "clear history in current session",
+		"!-*", "", "clear and save empty history log",
 		"!=!", "", "enable remotecmd mode",
 		"=!=", "", "disable remotecmd mode",
 		"\nEnvironment:", "", "",