diff --git a/src/builtins/builtin_history.c b/src/builtins/builtin_history.c
index c13719e..671638a 100644
--- a/src/builtins/builtin_history.c
+++ b/src/builtins/builtin_history.c
@@ -77,7 +77,7 @@ char *his_last_command(char *line,
 char *his_last_same_command(char *line,
     his_variable_t *his_variable, his_command_t *his_command)
 {
-    char *new_line = &line[1];
+    char *new_line = &line[his_variable->coord_variable + 1];
     char *new_str = NULL;
 
     for (int i = his_command->sz - 1; i >= 0; i--) {
@@ -101,7 +101,7 @@ char *his_last_same_command(char *line,
 char *his_id_command(char *line,
     his_variable_t *his_variable, his_command_t *his_command)
 {
-    int id = ((int)line[1] - 48) - 1;
+    int id = atoi(&line[his_variable->coord_variable + 1]);
     char *new_line;
     char *new_str = NULL;
 
diff --git a/src/history.h b/src/history.h
index b239d1c..2c423d7 100644
--- a/src/history.h
+++ b/src/history.h
@@ -35,6 +35,8 @@ typedef struct parsing_history_s {
     char *(*funct)(char *, his_variable_t *, his_command_t *);
 } parsing_history_t;
 
+extern const parsing_history_t tab_fnct[];
+
 int parse_history(char **pointer_line,
     size_t *buffer_len, size_t *buffer_sz, his_command_t **cmd_history);
 char *his_last_command(char *line,
diff --git a/src/shell.c b/src/shell.c
index b88556b..304d663 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -34,6 +34,8 @@ void debug_env_entries(env_t *env)
 static
 void check_basic_error(char const *buffer)
 {
+    if (buffer == NULL)
+        return;
     if (*buffer == '|')
         WRITE_CONST(STDERR_FILENO, "Invalid null command.\n");
     if (*buffer == '>' || *buffer == '<')
diff --git a/src/update_command.c b/src/update_command.c
index 988e48e..dd2d83d 100644
--- a/src/update_command.c
+++ b/src/update_command.c
@@ -8,9 +8,21 @@
 #include "builtins_handler.h"
 #include "u_str.h"
 
-his_command_t *save_command(char *cmd, his_command_t *cmd_history)
+static int check_cmd(char *cmd)
 {
     if (!cmd)
+        return 84;
+    for (int i = 0; cmd[i] != 0; i++)
+        if (cmd[i] == CHAR_HIST &&
+            (cmd[i + 1] != ' ' && cmd[i + 1] != '\t'
+            && cmd[i + 1] != '\0'))
+            return 84;
+    return 0;
+}
+
+his_command_t *save_command(char *cmd, his_command_t *cmd_history)
+{
+    if (check_cmd(cmd) == 84)
         return cmd_history;
     if (cmd_history->sz < 100) {
         cmd_history[cmd_history->sz] = set_cmd(cmd,
@@ -27,8 +39,9 @@ size_t update_command(char **buffer,
 
     buffer_len = u_strlen(*buffer);
     (*buffer)[buffer_len - 1] = '\0';
-    parse_history(buffer, &buffer_len,
-        buffer_sz, &builtin_handler->history_command);
+    if (parse_history(buffer, &buffer_len,
+        buffer_sz, &builtin_handler->history_command) == 84)
+        return -1;
     builtin_handler->history_command = save_command(*buffer,
         builtin_handler->history_command);
     return buffer_len;