diff --git a/include/include.h b/include/include.h
index ce10b5f..9205886 100644
--- a/include/include.h
+++ b/include/include.h
@@ -6,7 +6,7 @@
 /*   By: mcolonna <marvin@42.fr>                    +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2024/04/23 14:15:12 by mcolonna          #+#    #+#             */
-/*   Updated: 2024/04/25 16:53:06 by mcolonna         ###   ########.fr       */
+/*   Updated: 2024/04/25 17:47:02 by mcolonna         ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
@@ -73,6 +73,6 @@ void		fatal_error(const char *msg);
 
 // Get the PATH values.
 // Return a list of strings ended by NULL.
-const char	**get_path(const char **envp);
+char		**get_path(const char **envp);
 
 #endif
diff --git a/src/exec_command.c b/src/exec_command.c
new file mode 100644
index 0000000..f7d609d
--- /dev/null
+++ b/src/exec_command.c
@@ -0,0 +1,57 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   exec_command.c                                     :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: jschaft <cecile.schaft@orange.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2024/04/24 13:48:00 by jschaft           #+#    #+#             */
+/*   Updated: 2024/04/25 17:23:34 by mcolonna         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "include.h"
+
+// Free every element of tab, then tab itself.
+static void	free_tab(char **tab)
+{
+	int	i;
+
+	i = 0;
+	while (tab[i] != NULL)
+	{
+		free(tab[i]);
+		i++;
+	}
+	free(tab);
+}
+
+// TODO works with only one call (no pipe).
+// TODO is t_call.argv ended by NULL?
+static void	fork_exec(const char *path, t_command command, const char **envp)
+{
+	if (command.input_fd != 0)
+		dup2(command.input_fd, 0);
+	if (command.output_fd != 1)
+		dup2(command.output_fd, 1);
+	execve(path, command.calls[0]->argv, envp);
+}
+
+// TODO works with only one call (no pipe).
+int	execute_command(t_command command, const char **envp)
+{
+	const char	**path = get_path(envp);
+	pid_t		pid;
+	int			program_path;
+
+	program_path = search_path(path);
+	if (!program_path)
+		return (127);
+	pid = fork();
+	if (pid < 0)
+		return (1);
+	if (pid == 0)
+		fork_exec(program_path, command, envp);
+	free_tab(path);
+	return (0);
+}
diff --git a/src/path.c b/src/path.c
index 82b5a85..37ea53e 100644
--- a/src/path.c
+++ b/src/path.c
@@ -6,13 +6,14 @@
 /*   By: jschaft <cecile.schaft@orange.fr>          +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2023/11/16 12:07:26 by jschaft           #+#    #+#             */
-/*   Updated: 2024/04/24 13:26:41 by mcolonna         ###   ########.fr       */
+/*   Updated: 2024/04/25 17:30:05 by mcolonna         ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
 #include "include.h"
 
-const char	**get_path(const char **envp)
+// Get the path values from envp.
+char	**get_path(const char **envp)
 {
 	int			i;
 	char	**re;
@@ -24,5 +25,26 @@ const char	**get_path(const char **envp)
 	path = ft_substr(envp[i], 5, ft_strlen(envp[i]) - 5);
 	re = ft_split(path, ':');
 	free(path);
-	return ((const char **)re);
+	return (char **re);
+}
+
+// Search the program in PATH.
+// Returns the path of the program to use, or NULL if there is none.
+// TODO does it return the good path if there is several possibilities?
+const char	*search_path(
+		const t_memclass mc, const char **path, const char *prog)
+{
+	const t_memclass	mc_in = mem_newclass(fatal_error);
+	const char			*prog2 = str_join(fatal_error, mc_in, "/", prog);
+	int					i;
+
+	i = 0;
+	while (path[i] != NULL)
+	{
+		if (access(str_join(fatal_error, mc_in, path[i], prog2), X_OK) >= 0)
+			return (i);
+		i++;
+	}
+	mem_freeall(mc_in);
+	return (NULL);
 }