diff --git a/To b/To
deleted file mode 100644
index e69de29b..00000000
diff --git a/src/parser/input_checks.c b/src/parser/input_checks.c
new file mode 100644
index 00000000..7ae82f48
--- /dev/null
+++ b/src/parser/input_checks.c
@@ -0,0 +1,125 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   str_checks.c                                     :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: rocky <marvin@42.fr>                       +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2024/06/11 16:51:08 by rocky             #+#    #+#             */
+/*   Updated: 2024/06/11 16:53:40 by rocky            ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "tokens.h"
+
+
+int	check_operators(char *str)
+{
+	int	single_quotes;
+	int	double_quotes;
+	int	cmd_flag;
+
+	single_quotes = 0;
+	double_quotes = 0;
+	cmd_flag = 0;
+	if (*str == '&' || *str == '|')
+		return (1);
+	while (*str)
+	{
+
+		if (*str == "\'")
+			single_quotes++;
+		if (*str == "\"")
+			double_quotes++;
+		if (*str == '|' && !(single_quotes % 2) && !(double_quotes % 2))
+		{
+			if (cmd_flag)
+				return (1);
+			cmd_flag = 1;
+		}
+		else if (ft_strchr(" \t\n\r\v\f", *str) != NULL)
+			cmd_flag = 0;
+		str++;
+	}
+	if (cmd_flag)
+		return (1);
+	return (0);
+}
+
+char *exclude_delimiters(char *str)
+{
+	while (*str && (ft_strchr(" \t\n\r\v\f", *str) != NULL))
+		str++;
+	return (str);
+}
+
+int	valid_operator(char **str)
+{
+	char *start;
+
+	start = *str++;
+	if (*start == **str)
+		(*str)++;
+	*str = exclude_delimiters(*str);
+	if (**str == '<' || **str == '>' || **str == '|' || **str == '\0')
+		return (0);
+	return (1);
+}
+
+int	check_redirections(char *str)
+{
+	int	single_quotes;
+	int	double_quotes;
+
+	single_quotes = 0;
+	double_quotes = 0;
+	while (*str)
+	{
+		if (*str == "\'")
+			single_quotes++;
+		if (*str == "\"")
+			double_quotes++;
+		if ((!(single_quotes % 2) && !(double_quotes %2)) 
+			&& (*str == '>' || *str == '<'))
+		{
+			if (!valid_operator(&str))
+				return (1);
+		}
+		else
+			str++;
+	}
+	return (0);
+}
+
+int	check_open_quotes(const char *str)
+{
+	int	single_quote_open;
+	int	double_quote_open;
+
+	single_quote_open = 0;
+	double_quote_open = 0;
+	while (*str)
+	{
+		if (*str == '\'' && !double_quote_open)
+		{
+			single_quote_open = !single_quote_open;
+		}
+		else if (*str == '"' && !single_quote_open)
+			double_quote_open = !double_quote_open;
+		str++;
+	}
+	return (single_quote_open || double_quote_open);
+}
+
+int	str_error_checks(char *str)
+{
+	if (check_redirections(str))
+		ft_printf("str error: invalid redirection.\n");
+	else if (check_operators(str))
+		ft_printf("str error: invalid operator.\n");
+	else if (check_open_quotes(str))
+		ft_printf("str error: open quote.\n");
+	else
+		return (0);
+	return (1);
+}