diff --git a/src/parser/parser.c b/src/parser/parser.c
index cebfad9..15b4932 100644
--- a/src/parser/parser.c
+++ b/src/parser/parser.c
@@ -6,7 +6,7 @@
 /*   By: sede-san <sede-san@student.42madrid.com    +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2025/10/22 18:37:38 by sede-san          #+#    #+#             */
-/*   Updated: 2026/02/12 21:25:39 by sede-san         ###   ########.fr       */
+/*   Updated: 2026/02/13 08:17:43 by sede-san         ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
@@ -119,7 +119,7 @@ static void expand_variable(
 	int			end;
 
 	end = start;
-	while (ft_isalnum((*argument)[end]))
+	while (ft_isalnum((*argument)[end]) || (*argument)[end] == '_')
 		end++;
 	variable_name = ft_substr(*argument, start, end - start);
 	if (variable_name == NULL)