diff --git a/functions/ft_split.c b/functions/ft_split.c
new file mode 100644
index 0000000..78bcbaa
--- /dev/null
+++ b/functions/ft_split.c
@@ -0,0 +1,104 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_split.c                                         :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: bcaffere <bcaffere@student.21-school.ru    +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2021/05/01 19:37:15 by bcaffere          #+#    #+#             */
+/*   Updated: 2021/10/08 19:18:15 by bcaffere         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "../includes/pipex.h"
+
+static size_t	words_count(char *s, char c)
+{
+	size_t	i;
+	size_t	j;
+
+	i = 0;
+	j = 0;
+	while (*s)
+	{
+		if (*s != c)
+			i++;
+		else if (*s == c && i != 0)
+		{
+			j++;
+			i = 0;
+		}
+		s++;
+	}
+	if (i != 0)
+		j++;
+	return (j);
+}
+
+static char	*word(char *s, char c)
+{
+	char	*buf;
+
+	while (*s == c)
+		s++;
+	buf = s;
+	while (*buf && *buf != c)
+		buf++;
+	*buf = '\0';
+	return (ft_strdup(s));
+}
+
+static char	**free_arr(char **arr, char *s)
+{
+	size_t	i;
+
+	i = 0;
+	while (arr[i])
+	{
+		free(arr[i]);
+		i++;
+	}
+	free(arr);
+	free(s);
+	return (NULL);
+}
+
+static char	**worker(char **arr, char *s1, char c, size_t j)
+{
+	size_t	i;
+	char	*str;
+
+	str = s1;
+	i = 0;
+	while (i < j)
+	{
+		if (*s1 != c)
+		{
+			arr[i] = word(s1, c);
+			if (!arr[i])
+				return (free_arr(arr, s1));
+			s1 = s1 + ft_strlen(arr[i]);
+			i++;
+		}
+		s1++;
+	}
+	arr[i] = NULL;
+	free(str);
+	return (arr);
+}
+
+char	**ft_split(char const *s, char c)
+{
+	char	**w_arr;
+	char	*s1;
+	size_t	j;
+
+	s1 = ft_strdup(s);
+	if (!s1)
+		return (NULL);
+	j = words_count(s1, c);
+	w_arr = (char **)malloc(sizeof(char *) * (j + 1));
+	if (!w_arr)
+		return (NULL);
+	return (worker(w_arr, s1, c, j));
+}
diff --git a/functions/ft_strdup.c b/functions/ft_strdup.c
new file mode 100644
index 0000000..2caa217
--- /dev/null
+++ b/functions/ft_strdup.c
@@ -0,0 +1,31 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_strdup.c                                        :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: bcaffere <bcaffere@student.21-school.ru    +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2021/04/24 22:06:30 by bcaffere          #+#    #+#             */
+/*   Updated: 2021/10/08 19:24:56 by bcaffere         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "../includes/pipex.h"
+
+char	*ft_strdup(const char *src)
+{
+	char	*cp;
+	size_t	i;
+
+	i = 0;
+	cp = (char *)malloc(ft_strlen(src) + 1);
+	if (!cp)
+		return (NULL);
+	while (src[i])
+	{
+		cp[i] = src[i];
+		i++;
+	}
+	cp[i] = '\0';
+	return (cp);
+}
diff --git a/functions/ft_strjoin.c b/functions/ft_strjoin.c
new file mode 100644
index 0000000..42ca7fa
--- /dev/null
+++ b/functions/ft_strjoin.c
@@ -0,0 +1,39 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_strjoin.c                                       :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: bcaffere <bcaffere@student.21-school.ru    +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2021/04/18 19:26:05 by bcaffere          #+#    #+#             */
+/*   Updated: 2021/10/08 20:21:52 by bcaffere         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "../includes/pipex.h"
+
+char	*ft_strjoin(char const *s1, char const *s2)
+{
+	char	*j_str;
+	size_t	i;
+	size_t	j;
+
+	j_str = (char *)malloc(sizeof(char) * (ft_strlen(s1) + ft_strlen(s2) + 1));
+	if (!j_str)
+		return (NULL);
+	i = 0;
+	while (s1[i] != '\0')
+	{
+		j_str[i] = s1[i];
+		i++;
+	}
+	j = 0;
+	while (s2[j] != '\0')
+	{
+		j_str[i] = s2[j];
+		i++;
+		j++;
+	}
+	j_str[i] = '\0';
+	return (j_str);
+}
diff --git a/functions/ft_strncmp.c b/functions/ft_strncmp.c
new file mode 100644
index 0000000..33a51ec
--- /dev/null
+++ b/functions/ft_strncmp.c
@@ -0,0 +1,26 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_strncmp.c                                       :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: bcaffere <bcaffere@student.21-school.ru    +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2021/04/19 19:41:42 by bcaffere          #+#    #+#             */
+/*   Updated: 2021/10/08 17:46:35 by bcaffere         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "../includes/pipex.h"
+
+int	ft_strncmp(const char *s1, const char *s2, size_t n)
+{
+	while ((*s1 || *s2) && (n > 0))
+	{
+		if (*s1 != *s2)
+			return ((unsigned char)*s1 - (unsigned char)*s2);
+		s1++;
+		s2++;
+		n--;
+	}
+	return (0);
+}