diff --git a/README.md b/README.md
index 0b91b92..d3686bf 100644
--- a/README.md
+++ b/README.md
@@ -1,12 +1,11 @@
 # 42sh - A POSIX shell with a bad name
 
-42sh is a project aiming to implement a POSIX-compliant shell written in C with only the standard library.
-Source de is fully documented with the doxygen format so you can easily understand how the project works by exploring it. 
-
-> **Note** This is a school project, therefore it probably won't interest you if you are looking for something useful.
+42sh is a shcool project aiming to implement a POSIX compliant shell in C.
 
 ## Getting started
 
+TODO
+
 ### Build
 run this command:
     `autoreconf --force --verbose --install`
@@ -17,43 +16,27 @@ run this command:
 then:
     `make`
 
-#### Build with ASan
+#### asan
 run this command:
     `./configure CFLAGS='-std=c99 -Werror -Wall -Wextra -Wvla -g -fsanitize=address'`
-
 or for MacOS (Jean Here):
     `./configure CFLAGS='-std=c99 -Werror -Wall -Wextra -Wvla -I/opt/homebrew/include' LDFLAGS='-L/opt/homebrew/lib'`
-    
+
 then:
     `make check`
 
-## Project status
-
-### Implemented features
-
-* **Command Execution:** `$PATH` search and binary execution (via `fork` and `execvp`) with error return code handling.
-* **Built-ins:** Native implementation of `echo`, `cd`, `exit`, `export`, `unset`, `set`, `.`, `true`, `false`, as well as loop management with `break` and `continue`.
-* **Control Structures:** * Conditions: `if / then / elif / else / fi`.
-    * Loops: `while`, `until` and `for`.
-* **Logical Operators:** Command chaining with `&&`, `||` and negation with `!`.
-* **Pipelines and Redirections:** * Full management of pipes `|` to connect the output of one process to the input of another.
-    * Single and multiple redirections: `>`, `<`, `>>`, `>&`, `<&`, `<>`.
-* **Variables Management:** Assignment, variable expansion, and special variables handling like `$?` (return code of the last command).
-* **Command Grouping:** Execution blocks `{ ... }` and subshells creation `( ... )`.
-* **Quoting:** Support for weak (`"`) and strong (`'`) quoting for special characters escaping.
-
-## Architecture
-
-The shell operates on a classic compilation/interpretation pipeline:
-
-1. **Lexer (Lexical Analysis):** Reads standard input (or script) character by character and generates a stream of "Tokens" (Words, Operators, Redirections).
-2. **Parser (Syntax Analysis):** Syntax analyzer that transforms the token stream into a complex Abstract Syntax Tree (AST). This module strictly manages the nesting of control structures and enforces the rigid grammar of the Shell Command Language.
-3. **Execution (AST Traversal):** The tree is traversed recursively. Redirections modify file descriptors (`dup2`), child processes are created (`fork`), and commands are executed.
-
-
 ## Authors
 
-- Guillem George
 - Matteo Flebus
 - Jean Herail
 - William Valenduc
+- Guillem George
+
+## Project status
+
+WIP
+
+## TODO
+
+# Autotools
+implement functions in all .c files to see if everything compiles.
diff --git a/src/Makefile.am b/src/Makefile.am
index 5f9fa1d..210cac1 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -18,9 +18,9 @@ bin_PROGRAMS = 42sh
 		parser/libparser.a \
 		lexer/liblexer.a \
 		io_backend/libio_backend.a \
-		utils/libutils.a \
 		execution/libexecution.a \
-		expansion/libexpansion.a
+		expansion/libexpansion.a \
+		utils/libutils.a
 
 # ================ TESTS ================
 
diff --git a/src/execution/execution.c b/src/execution/execution.c
index 28726e5..46bbfcb 100644
--- a/src/execution/execution.c
+++ b/src/execution/execution.c
@@ -9,7 +9,6 @@
 
 #include "../expansion/expansion.h"
 #include "../utils/hash_map/hash_map.h"
-#include "../utils/vars/vars.h"
 
 // Refactored: delegates to helpers in execution_helpers.c
 #include "execution_helpers.h"
@@ -19,55 +18,27 @@ int execution(struct ast *ast, struct hash_map *vars)
     if (!ast)
         return 0;
 
-    int res;
     switch (ast->type)
     {
     case AST_VOID:
     case AST_END:
-        res = 0;
-        break;
+        return 0;
     case AST_CMD: {
         struct ast_command *command = ast_get_command(ast);
         if (!expand(command, vars))
             fprintf(stderr, "Error: Variable expansion failed\n");
 
-        res = exec_ast_command(command, vars);
-        break;
+        return exec_ast_command(command, vars);
     }
     case AST_IF:
-        res = exec_ast_if(ast_get_if(ast), vars);
-        break;
+        return exec_ast_if(ast_get_if(ast), vars);
     case AST_LIST:
-        res = exec_ast_list(ast_get_list(ast), vars);
-        break;
+        return exec_ast_list(ast_get_list(ast), vars);
     case AST_AND_OR:
-        res = exec_ast_and_or(ast_get_and_or(ast), vars);
-        break;
+        return exec_ast_and_or(ast_get_and_or(ast), vars);
     case AST_LOOP:
-        res = exec_ast_loop(ast_get_loop(ast), vars);
-        break;
-    case AST_SUBSHELL:
-        res = exec_ast_subshell(ast_get_subshell(ast), vars);
-        break;
+        return exec_ast_loop(ast_get_loop(ast), vars);
     default:
-        res = 127;
-        break;
-    }
-
-    if (res == EXEC_SIGNAL_EXIT)
-    {
-        char *exit_val_str = get_var(vars, "EXIT_VALUE");
-        if (exit_val_str == NULL)
-        {
-            fprintf(
-                stderr,
-                "Internal error: could not retrieve return value from exit\n");
-            return 2;
-        }
-        return atoi(exit_val_str);
-    }
-    else
-    {
-        return res;
+        return 127;
     }
 }
diff --git a/src/execution/execution_helpers.c b/src/execution/execution_helpers.c
index 12d4e1f..5157290 100644
--- a/src/execution/execution_helpers.c
+++ b/src/execution/execution_helpers.c
@@ -14,8 +14,6 @@
 #include "../utils/vars/vars.h"
 #include "execution.h"
 
-// === Static functions
-
 static int open_redir_file(const struct ast_redir *redir, int *flags, int *mode)
 {
     *mode = 0644;
@@ -123,35 +121,10 @@ static char **list_to_argv(struct list *command_list)
     return argv;
 }
 
-/*
- * @brief parses string and returns the represented (unsigned) number
- * @return the number contained by the string or -1 if number is invalid
- */
-static int atou(char *str)
-{
-    if (str == NULL || *str == '\0')
-        return -1;
-
-    int result = 0;
-    size_t i = 0;
-    while (str[i] != '\0')
-    {
-        if (str[i] < '0' || str[i] > '9')
-            return -1;
-
-        result *= 10;
-        result += str[i] - '0';
-        i++;
-    }
-
-    return result;
-}
-
 static int try_builtin(char **argv, struct hash_map *vars);
 
 static int builtin_break(char **argv);
 static int builtin_continue(char **argv);
-static int builtin_unset(char **argv, struct hash_map *vars);
 
 static int exec_assignment(struct list *assignment_list, struct hash_map *vars)
 {
@@ -165,18 +138,12 @@ static int exec_assignment(struct list *assignment_list, struct hash_map *vars)
         struct ast_assignment *assignment =
             ast_get_assignment(assignment_list->data);
 
-        if (assignment->global)
-        {
-            setenv(assignment->name, assignment->value, 1);
-        }
         set_var_copy(vars, assignment->name, assignment->value);
         assignment_list = assignment_list->next;
     }
     return 0;
 }
 
-// === Functions
-
 int exec_ast_command(struct ast_command *command, struct hash_map *vars)
 {
     exec_assignment(command->assignments, vars);
@@ -238,48 +205,24 @@ int exec_ast_if(struct ast_if *if_node, struct hash_map *vars)
     if (if_node == NULL)
         return 2;
     int cond = execution(if_node->condition, vars);
-    if (cond == EXEC_SIGNAL_BREAK || cond == EXEC_SIGNAL_CONTINUE
-        || cond == EXEC_SIGNAL_EXIT)
+    if (cond == EXEC_SIGNAL_BREAK || cond == EXEC_SIGNAL_CONTINUE)
         return cond;
     if (cond == 0)
     {
         int r = execution(if_node->then_clause, vars);
+        if (r == EXEC_SIGNAL_BREAK || r == EXEC_SIGNAL_CONTINUE)
+            return r;
         return r;
     }
     else
     {
         int r = execution(if_node->else_clause, vars);
+        if (r == EXEC_SIGNAL_BREAK || r == EXEC_SIGNAL_CONTINUE)
+            return r;
         return r;
     }
 }
 
-int exec_ast_subshell(struct ast_subshell *subshell_node,
-                      struct hash_map *vars)
-{
-    pid_t pid = fork();
-    if (pid < 0)
-    {
-        perror("fork");
-        return 1;
-    }
-
-    if (pid == 0)
-    {
-        int res = execution(subshell_node->child, vars);
-        _exit(res);
-    }
-
-    int status = 0;
-    waitpid(pid, &status, 0);
-
-    if (WIFEXITED(status))
-    {
-        return WEXITSTATUS(status);
-    }
-
-    return 1;
-}
-
 int exec_ast_list(struct ast_list *list_node, struct hash_map *vars)
 {
     struct list *cur = list_node->children;
@@ -291,8 +234,7 @@ int exec_ast_list(struct ast_list *list_node, struct hash_map *vars)
         {
             int child_ret = execution(child, vars);
             if (child_ret == EXEC_SIGNAL_BREAK
-                || child_ret == EXEC_SIGNAL_CONTINUE
-                || child_ret == EXEC_SIGNAL_EXIT)
+                || child_ret == EXEC_SIGNAL_CONTINUE)
                 return child_ret;
             ret = child_ret;
         }
@@ -304,14 +246,16 @@ int exec_ast_list(struct ast_list *list_node, struct hash_map *vars)
 int exec_ast_and_or(struct ast_and_or *ao_node, struct hash_map *vars)
 {
     int left_ret = execution(ao_node->left, vars);
-    if (left_ret == EXEC_SIGNAL_BREAK || left_ret == EXEC_SIGNAL_CONTINUE
-        || left_ret == EXEC_SIGNAL_EXIT)
+    if (left_ret == EXEC_SIGNAL_BREAK || left_ret == EXEC_SIGNAL_CONTINUE)
         return left_ret;
     if (ao_node->type == AST_AND_OR_TYPE_AND)
     {
         if (left_ret == 0)
         {
             int right_ret = execution(ao_node->right, vars);
+            if (right_ret == EXEC_SIGNAL_BREAK
+                || right_ret == EXEC_SIGNAL_CONTINUE)
+                return right_ret;
             return right_ret;
         }
         return left_ret;
@@ -321,6 +265,9 @@ int exec_ast_and_or(struct ast_and_or *ao_node, struct hash_map *vars)
         if (left_ret != 0)
         {
             int right_ret = execution(ao_node->right, vars);
+            if (right_ret == EXEC_SIGNAL_BREAK
+                || right_ret == EXEC_SIGNAL_CONTINUE)
+                return right_ret;
             return right_ret;
         }
         return left_ret;
@@ -507,21 +454,13 @@ static int builtin_false(char **argv)
     return 1;
 }
 
-static int builtin_exit(char **argv, struct hash_map *vars)
+static int builtin_exit(char **argv)
 {
     int exit_val = 0;
     if (argv[1])
-    {
-        exit_val = atou(argv[1]);
-        if (exit_val == -1)
-        {
-            fprintf(stderr, "exit: Illegal number %s\n", argv[1]);
-            return 2;
-        }
-    }
-
-    set_var_int(vars, "EXIT_VALUE", exit_val);
-    return EXEC_SIGNAL_EXIT;
+        exit_val = atoi(argv[1]);
+    exit(exit_val);
+    return exit_val;
 }
 
 static int builtin_cd(char **argv, struct hash_map *vars)
@@ -548,23 +487,6 @@ static int builtin_cd(char **argv, struct hash_map *vars)
     return 0;
 }
 
-static int builtin_unset(char **argv, struct hash_map *vars)
-{
-    if (!argv)
-        return 0;
-    for (int i = 1; argv[i]; i++)
-    {
-        const char *name = argv[i];
-        if (name == NULL || name[0] == '\0')
-            continue;
-        // remove from shell variables
-        hash_map_remove(vars, name);
-        // remove from environment variables
-        unsetenv(name);
-    }
-    return 0;
-}
-
 /**
  * @brief Tries to execute a builtin command if the command matches a builtin
  *
@@ -578,8 +500,6 @@ static int try_builtin(char **argv, struct hash_map *vars)
 
     if (strcmp(argv[0], "echo") == 0)
         return builtin_echo(argv);
-    if (strcmp(argv[0], "unset") == 0)
-        return builtin_unset(argv, vars);
     if (strcmp(argv[0], "true") == 0)
         return builtin_true(argv);
     if (strcmp(argv[0], "false") == 0)
@@ -589,7 +509,7 @@ static int try_builtin(char **argv, struct hash_map *vars)
     if (strcmp(argv[0], "continue") == 0)
         return builtin_continue(argv);
     if (strcmp(argv[0], "exit") == 0)
-        return builtin_exit(argv, vars);
+        return builtin_exit(argv);
     if (strcmp(argv[0], "cd") == 0)
         return builtin_cd(argv, vars);
 
diff --git a/src/execution/execution_helpers.h b/src/execution/execution_helpers.h
index 8a56e18..530b4dc 100644
--- a/src/execution/execution_helpers.h
+++ b/src/execution/execution_helpers.h
@@ -7,15 +7,12 @@
 // Special execution signals used internally to implement loop control
 #define EXEC_SIGNAL_CONTINUE (-2)
 #define EXEC_SIGNAL_BREAK (-3)
-#define EXEC_SIGNAL_EXIT (-4)
 
 int exec_ast_command(struct ast_command *command, struct hash_map *vars);
 int exec_ast_if(struct ast_if *if_node, struct hash_map *vars);
 int exec_ast_list(struct ast_list *list_node, struct hash_map *vars);
 int exec_ast_and_or(struct ast_and_or *ao_node, struct hash_map *vars);
 int exec_ast_loop(struct ast_loop *loop_node, struct hash_map *vars);
-int exec_ast_subshell(struct ast_subshell *subshell_node,
-                        struct hash_map *vars);
 
 void unset_all_redir(struct list *redir_list);
 #endif // EXECUTION_HELPERS_H
diff --git a/src/expansion/expansion.c b/src/expansion/expansion.c
index e8f8577..4fea985 100644
--- a/src/expansion/expansion.c
+++ b/src/expansion/expansion.c
@@ -1,6 +1,4 @@
 #define _POSIX_C_SOURCE 200809L
-#include "expansion.h"
-
 #include <ctype.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -117,40 +115,6 @@ static bool expand_var(char **str, size_t pos, const struct hash_map *vars)
     return false;
 }
 
-size_t parse_subshell_str(char *str, char **res)
-{
-    size_t i = 1; // skip the '('
-    int paren_count = 1;
-
-    if (str[i] == ')')
-    {
-        // empty subshell
-        *res = NULL;
-        return 0;
-    }
-
-    while (str[i] != 0)
-    {
-        if (str[i] == '(')
-            paren_count++;
-        else if (str[i] == ')')
-        {
-            paren_count--;
-
-            if (paren_count == 0)
-            {
-                *res = strndup(str + 1, i - 1);
-                return i + 1;
-            }
-        }
-        i++;
-    }
-
-    // error: parenthesis not closed
-    *res = NULL;
-    return 0;
-}
-
 bool expand(struct ast_command *command, const struct hash_map *vars)
 {
     if (command == NULL)
@@ -158,42 +122,34 @@ bool expand(struct ast_command *command, const struct hash_map *vars)
 
     char *str;
     size_t len;
-    enum quote_state quotes;
+    bool in_quotes;
     struct list *l = command->command;
 
     while (l != NULL)
     {
-        quotes = NO_QUOTE;
+        in_quotes = false;
         str = (char *)l->data;
         len = strlen(str);
 
         for (size_t i = 0; str[i] != 0; i++)
         {
-            if (str[i] == '\'' || str[i] == '\"')
+            if (str[i] == '\'')
             {
-                if (quotes == NO_QUOTE)
-                {
-                    quotes = (str[i] == '\'') ? SINGLE_QUOTE : DOUBLE_QUOTE;
-                }
-                else if ((quotes == SINGLE_QUOTE && str[i] == '\'')
-                         || (quotes == DOUBLE_QUOTE && str[i] == '\"'))
-                {
-                    quotes = NO_QUOTE;
-                }
-                else
-                {
-                    // inside the other quote type, do nothing
-                    continue;
-                }
-
-                // remove quote
+                // remove single quote
+                in_quotes = !in_quotes;
                 memmove(str + i, str + i + 1, strlen(str + i + 1) + 1);
                 i--;
             }
-            else if (quotes == SINGLE_QUOTE)
+            else if (in_quotes)
             {
                 continue; // do nothing
             }
+            else if (str[i] == '\"')
+            {
+                // remove double quote
+                memmove(str + i, str + i + 1, strlen(str + i + 1) + 1);
+                i--;
+            }
             else if (str[i] == '$' && str[i + 1] != 0 && !isspace(str[i + 1]))
             {
                 // variable expansion
@@ -205,20 +161,21 @@ bool expand(struct ast_command *command, const struct hash_map *vars)
             }
         }
 
-        // if (quotes != NO_QUOTE)
-        // {
-        //     // error: quote not closed
-        //     fprintf(stderr, "Error: quote not closed in string: %s\n", str);
-        //     return false;
-        // }
+        if (in_quotes)
+        {
+            // error: quote not closed
+            fprintf(stderr, "Error: quote not closed in string: %s\n", str);
+            return false;
+        }
 
         if (len != strlen(str))
         {
             char *new_str = realloc(str, strlen(str) + 1);
             if (new_str == NULL)
+            {
                 // error: realloc fail
                 return false;
-
+            }
             l->data = new_str;
         }
 
diff --git a/src/expansion/expansion.h b/src/expansion/expansion.h
index ce22e38..420ed02 100644
--- a/src/expansion/expansion.h
+++ b/src/expansion/expansion.h
@@ -7,13 +7,6 @@
 #include "../utils/ast/ast.h"
 #include "../utils/hash_map/hash_map.h"
 
-enum quote_state
-{
-    NO_QUOTE,
-    SINGLE_QUOTE,
-    DOUBLE_QUOTE
-};
-
 /**
  * Parse a variable from a string starting with '$'.
  * @param str The input string starting with '$'. It must start with '$'.
@@ -23,15 +16,6 @@ enum quote_state
  */
 size_t parse_var_name(char *str, char **res);
 
-/**
- * Parse a subshell string enclosed in parentheses.
- * @param str The input string starting with '('. It must start with '('.
- * @param res Pointer to a char pointer that will be set to the extracted
- * subshell string.
- * @return The number of characters processed in the input string.
- */
-size_t parse_subshell_str(char *str, char **res);
-
 /**
  * Expand variables in an AST command using the provided variable map.
  * @param command The AST command to expand.
diff --git a/src/lexer/lexer_utils.c b/src/lexer/lexer_utils.c
index 53c3603..1f40a69 100644
--- a/src/lexer/lexer_utils.c
+++ b/src/lexer/lexer_utils.c
@@ -76,7 +76,7 @@ static void set_token_keyword(struct token *tok, char *begin, ssize_t size)
         tok->type = TOKEN_FOR;
     else if (strncmp(begin, "while", size) == 0 && size == 5)
         tok->type = TOKEN_WHILE;
-    else if (strncmp(begin, "until", size) == 0 && size == 5)
+    else if (strncmp(begin, "until", size) == 0 && size == 4)
         tok->type = TOKEN_UNTIL;
     else if (strncmp(begin, "do", size) == 0 && size == 2)
         tok->type = TOKEN_DO;
diff --git a/src/main.c b/src/main.c
index cf3b791..02320b9 100644
--- a/src/main.c
+++ b/src/main.c
@@ -7,9 +7,70 @@
 #include "lexer/lexer.h"
 #include "parser/parser.h"
 #include "utils/args/args.h"
-#include "utils/main_loop/main_loop.h"
 #include "utils/vars/vars.h"
 
+// === Error codes
+
+#define SUCCESS 0
+#define ERR_INPUT_PROCESSING 2
+#define ERR_MALLOC 3
+#define ERR_GENERIC 4
+
+// === Functions
+
+/* @brief: frees the hash map.
+ * @return: always ERR_INPUT_PROCESSING.
+ */
+static int err_input(struct hash_map **vars, struct lexer_context *ctx)
+{
+    hash_map_free(vars);
+    destroy_lexer_context(ctx);
+    return ERR_INPUT_PROCESSING;
+}
+
+static int main_loop(struct lexer_context *ctx, struct hash_map *vars)
+{
+    int return_code = SUCCESS;
+    // init parser
+    if (!parser_init())
+    {
+        perror("parser initialization failed.");
+    }
+
+    // Retrieve and build first AST
+    struct ast *command_ast = get_ast(ctx);
+
+    // Main parse-execute loop
+    while (command_ast != NULL && command_ast->type != AST_END)
+    {
+        if (command_ast->type != AST_VOID)
+        {
+            // Execute AST
+            return_code = execution(command_ast, vars);
+
+            // set $? variable
+            set_var_int(vars, "?", return_code);
+        }
+
+        ast_free(&command_ast);
+
+        // Retrieve and build next AST
+        command_ast = get_ast(ctx);
+    }
+
+    if (command_ast == NULL)
+        return err_input(&vars, ctx);
+
+    // === free
+
+    ast_free(&command_ast);
+    parser_close();
+    hash_map_free(&vars);
+    destroy_lexer_context(ctx);
+
+    return return_code;
+}
+
 int main(int argc, char **argv)
 {
     struct hash_map *vars = vars_init();
@@ -56,16 +117,7 @@ int main(int argc, char **argv)
     // init lexer context
     struct lexer_context *ctx = calloc(1, sizeof(struct lexer_context));
 
-    // init parser
-    if (!parser_init())
-    {
-        perror("parser initialization failed.");
-        return err_input(&vars, ctx);
-    }
-
     return_code = main_loop(ctx, vars);
 
-    parser_close();
-
     return return_code;
 }
diff --git a/src/parser/grammar_advanced.c b/src/parser/grammar_advanced.c
index d1b7efa..ae652a1 100644
--- a/src/parser/grammar_advanced.c
+++ b/src/parser/grammar_advanced.c
@@ -220,18 +220,18 @@ struct ast *parse_while(struct lexer_context *ctx)
     }
     POP_TOKEN();
 
-    return parse_loop(ctx, false);
+    return parse_loop(ctx, true);
 }
 
 struct ast *parse_until(struct lexer_context *ctx)
 {
     struct token *token = PEEK_TOKEN();
 
-    // 'until'
+    // 'while'
     if (token->type != TOKEN_UNTIL)
     {
         perror(
-            "Internal error: expected a TOKEN_UNTIL but got a different type");
+            "Internal error: expected a TOKEN_WHILE but got a different type");
         return NULL;
     }
     POP_TOKEN();
diff --git a/src/parser/grammar_basic.c b/src/parser/grammar_basic.c
index 92113fe..d86abb6 100644
--- a/src/parser/grammar_basic.c
+++ b/src/parser/grammar_basic.c
@@ -372,45 +372,28 @@ struct ast *parse_shell_command(struct lexer_context *ctx)
     struct token *token = PEEK_TOKEN();
     struct ast *result = NULL;
 
-    // '{'
-    if (token->type == TOKEN_LEFT_BRACKET)
+    // Grouping
+    // '(' or '{'
+    if (token->type == TOKEN_LEFT_BRACKET || token->type == TOKEN_LEFT_PAREN)
     {
         POP_TOKEN();
         result = parse_compound_list(ctx);
         if (result == NULL)
             return NULL;
 
-        // '}'
+        // ')' or '}'
         token = PEEK_TOKEN();
-        if (token->type == TOKEN_LEFT_BRACKET)
+        if (token->type == TOKEN_LEFT_BRACKET
+            || token->type == TOKEN_LEFT_PAREN)
         {
             ast_free(&result);
-            perror("Syntax error: bracket mismatch");
+            perror("Syntax error: bracket/parenthesis mismatch");
             return NULL;
         }
 
         POP_TOKEN();
         return result;
     }
-    // '('
-    else if (token->type == TOKEN_LEFT_PAREN)
-    {
-        POP_TOKEN();
-        result = parse_compound_list(ctx);
-        if (result == NULL)
-            return NULL;
-
-        // ')'
-        token = PEEK_TOKEN();
-        if (token->type == TOKEN_LEFT_PAREN)
-        {
-            ast_free(&result);
-            perror("Syntax error: parenthesis mismatch");
-            return NULL;
-        }
-        POP_TOKEN();
-        return ast_create_subshell(result);
-    }
     else if (is_first(*token, RULE_IF))
     {
         return parse_if_rule(ctx);
diff --git a/src/utils/Makefile.am b/src/utils/Makefile.am
index e40612e..17454d2 100644
--- a/src/utils/Makefile.am
+++ b/src/utils/Makefile.am
@@ -20,9 +20,7 @@ libutils_a_SOURCES =  \
 	ast/ast_loop.c \
 	args/args.c \
 	vars/vars.c \
-	main_loop/main_loop.c \
 	ast/ast_assignment.c \
-	ast/ast_subshell.c \
 	ast/ast_function.c
 
 libutils_a_CPPFLAGS = -I$(top_srcdir)/src
diff --git a/src/utils/ast/ast.c b/src/utils/ast/ast.c
index d16a9cb..5baaf6a 100644
--- a/src/utils/ast/ast.c
+++ b/src/utils/ast/ast.c
@@ -11,7 +11,8 @@ void ast_free(struct ast **node)
 {
     if (node == NULL || *node == NULL)
     {
-        fprintf(stderr,
+        fprintf(
+            stderr,
             "WARNING: Internal error: failed to free AST node (NULL argument)");
         return;
     }
@@ -51,16 +52,14 @@ void ast_free(struct ast **node)
     case AST_FUNCTION:
         ast_free_function(ast_get_function(*node));
         break;
-    case AST_SUBSHELL:
-        ast_free_subshell(ast_get_subshell(*node));
-        break;
     case AST_VOID:
     case AST_END:
         break;
 
     default:
-        fprintf(stderr, "WARNING: Internal error:"
-                " failed to free an AST node (Unknown type)");
+        fprintf(stderr,
+                "WARNING: Internal error: failed to free an AST node (Unknown "
+                "type)");
         return;
     }
 
@@ -171,4 +170,4 @@ void ast_print_dot(struct ast *ast)
     fprintf(dot_pipe, "}\n");
     pclose(dot_pipe);
 }
- */
+ */
\ No newline at end of file
diff --git a/src/utils/ast/ast.h b/src/utils/ast/ast.h
index 2eac62f..12abee5 100644
--- a/src/utils/ast/ast.h
+++ b/src/utils/ast/ast.h
@@ -15,6 +15,5 @@
 #include "ast_redir.h"
 #include "ast_void.h"
 #include "ast_word.h"
-#include "ast_subshell.h"
 
 #endif /* ! AST_H */
diff --git a/src/utils/ast/ast_base.h b/src/utils/ast/ast_base.h
index de7dcfa..e1c7b07 100644
--- a/src/utils/ast/ast_base.h
+++ b/src/utils/ast/ast_base.h
@@ -18,8 +18,7 @@ enum ast_type
     AST_NEG,
     AST_LOOP,
     AST_ASSIGNMENT,
-    AST_FUNCTION,
-    AST_SUBSHELL
+    AST_FUNCTION
 };
 
 struct ast
diff --git a/src/utils/ast/ast_subshell.c b/src/utils/ast/ast_subshell.c
deleted file mode 100644
index 36efd6f..0000000
--- a/src/utils/ast/ast_subshell.c
+++ /dev/null
@@ -1,31 +0,0 @@
-#include "ast_subshell.h"
-
-bool ast_is_subshell(struct ast *node)
-{
-    return node != NULL && node->type == AST_SUBSHELL;
-}
-
-struct ast_subshell *ast_get_subshell(struct ast *node)
-{
-    if (ast_is_subshell(node))
-        return (struct ast_subshell *)node->data;
-    return NULL;
-}
-
-struct ast *ast_create_subshell(struct ast *child)
-{
-    struct ast_subshell *subshell = calloc(1, sizeof(struct ast_subshell));
-    if (subshell == NULL)
-        return NULL;
-    subshell->child = child;
-
-    return ast_create(AST_SUBSHELL, subshell);
-}
-
-void ast_free_subshell(struct ast_subshell *subshell)
-{
-    if (!subshell)
-        return;
-    ast_free(&subshell->child);
-    free(subshell);
-}
diff --git a/src/utils/ast/ast_subshell.h b/src/utils/ast/ast_subshell.h
deleted file mode 100644
index a4648ef..0000000
--- a/src/utils/ast/ast_subshell.h
+++ /dev/null
@@ -1,19 +0,0 @@
-#ifndef AST_SUBSHELL_H
-#define AST_SUBSHELL_H
-
-#include "ast_base.h"
-
-struct ast_subshell
-{
-    struct ast *child;
-};
-
-bool ast_is_subshell(struct ast *node);
-
-struct ast_subshell *ast_get_subshell(struct ast *node);
-
-struct ast *ast_create_subshell(struct ast *child);
-
-void ast_free_subshell(struct ast_subshell *subshell);
-
-#endif /* ! AST_SUBSHELL_H */
\ No newline at end of file
diff --git a/src/utils/hash_map/hash_map.c b/src/utils/hash_map/hash_map.c
index 0da4fc4..b07b63d 100644
--- a/src/utils/hash_map/hash_map.c
+++ b/src/utils/hash_map/hash_map.c
@@ -7,8 +7,6 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "../ast/ast.h"
-
 /*
 ** Hash the key using FNV-1a 32 bits hash algorithm.
 */
@@ -38,14 +36,6 @@ static void destroy_pair_list(struct pair_list **p)
     *p = NULL;
 }
 
-static void destroy_pair_list_ast(struct pair_list **p)
-{
-    free((char *)(*p)->key);
-    ast_free((*p)->value);
-    free((*p));
-    *p = NULL;
-}
-
 struct hash_map *hash_map_init(size_t size)
 {
     struct hash_map *p = malloc(sizeof(struct hash_map));
@@ -130,29 +120,6 @@ void hash_map_free(struct hash_map **hash_map)
     }
 }
 
-void hash_map_free_ast(struct hash_map **hash_map)
-{
-    struct pair_list *l;
-    struct pair_list *prev;
-
-    if (hash_map != NULL && *hash_map != NULL)
-    {
-        for (size_t i = 0; i < (*hash_map)->size; i++)
-        {
-            l = (*hash_map)->data[i];
-            while (l != NULL)
-            {
-                prev = l;
-                l = l->next;
-                destroy_pair_list_ast(&prev);
-            }
-        }
-        free((*hash_map)->data);
-        free(*hash_map);
-        *hash_map = NULL;
-    }
-}
-
 void hash_map_foreach(struct hash_map *hash_map,
                       void (*fn)(const char *, const void *))
 {
diff --git a/src/utils/main_loop/main_loop.c b/src/utils/main_loop/main_loop.c
deleted file mode 100644
index 362f640..0000000
--- a/src/utils/main_loop/main_loop.c
+++ /dev/null
@@ -1,111 +0,0 @@
-#define _POSIX_C_SOURCE 200809L
-
-#include "main_loop.h"
-
-// === Includes
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/wait.h>
-
-#include "../../execution/execution.h"
-#include "../../io_backend/io_backend.h"
-#include "../../lexer/lexer.h"
-#include "../../parser/parser.h"
-#include "../args/args.h"
-#include "../vars/vars.h"
-
-// === Functions
-
-int err_input(struct hash_map **vars, struct lexer_context *ctx)
-{
-    hash_map_free(vars);
-    destroy_lexer_context(ctx);
-    return ERR_INPUT_PROCESSING;
-}
-
-int main_loop(struct lexer_context *ctx, struct hash_map *vars)
-{
-    int return_code = SUCCESS;
-
-    // Retrieve and build first AST
-    struct ast *command_ast = get_ast(ctx);
-
-    // Main parse-execute loop
-    while (command_ast != NULL && command_ast->type != AST_END)
-    {
-        if (command_ast->type != AST_VOID)
-        {
-            // Execute AST
-            return_code = execution(command_ast, vars);
-
-            // set $? variable
-            set_var_int(vars, "?", return_code);
-        }
-
-        ast_free(&command_ast);
-
-        // Retrieve and build next AST
-        command_ast = get_ast(ctx);
-    }
-
-    if (command_ast == NULL)
-        return err_input(&vars, ctx);
-
-    // === free
-
-    ast_free(&command_ast);
-    hash_map_free(&vars);
-    destroy_lexer_context(ctx);
-
-    return return_code;
-}
-
-/* @brief: initializes a lexer context from a command string.
- * @return: pointer to the lexer context, or NULL on failure.
- */
-static struct lexer_context *lexer_init_from_string(char *command)
-{
-    // Create a lexer context from the command string
-    struct lexer_context *ctx = calloc(1, sizeof(struct lexer_context));
-    if (ctx == NULL)
-        return NULL;
-
-    ctx->end_previous_token = strdup(command);
-    if (ctx->end_previous_token == NULL)
-    {
-        free(ctx);
-        return NULL;
-    }
-    ctx->remaining_chars = strlen(command);
-
-    return ctx;
-}
-
-int start_subshell(struct hash_map **parent_vars, char *command)
-{
-    int fd = fork();
-    if (fd < 0)
-        return ERR_GENERIC;
-
-    else if (fd == 0) // Child process
-    {
-        struct lexer_context *ctx = lexer_init_from_string(command);
-        if (ctx == NULL)
-            return ERR_MALLOC;
-        int return_code = main_loop(ctx, *parent_vars);
-        exit(return_code);
-    }
-    else // Parent process
-    {
-        int status;
-        if (waitpid(fd, &status, 0) == -1)
-            return ERR_GENERIC;
-        if (WIFEXITED(status))
-            return WEXITSTATUS(status);
-        else
-            return ERR_GENERIC;
-    }
-}
diff --git a/src/utils/main_loop/main_loop.h b/src/utils/main_loop/main_loop.h
deleted file mode 100644
index 286c5b0..0000000
--- a/src/utils/main_loop/main_loop.h
+++ /dev/null
@@ -1,31 +0,0 @@
-#ifndef MAIN_LOOP_H
-#define MAIN_LOOP_H
-
-#include "../../utils/vars/vars.h"
-#include "../../lexer/lexer.h"
-
-// === Error codes
-#define SUCCESS 0
-#define ERR_INPUT_PROCESSING 2
-#define ERR_MALLOC 3
-#define ERR_GENERIC 4
-
-/* @brief: main loop called from main.
- * @return: exit code.
- */
-int main_loop(struct lexer_context *ctx, struct hash_map *vars);
-
-/*
- * @brief: frees the hash map and lexer context.
- * @return: ERR_INPUT_PROCESSING.
- */
-int err_input(struct hash_map **vars, struct lexer_context *ctx);
-
-/*
- * @brief: starts a subshell and builds the intern lexer context
- * from the string.
- * @return: exit code of the subshell.
- */
-int start_subshell(struct hash_map **parent_vars, char *command);
-
-#endif /* MAIN_LOOP_H */
\ No newline at end of file
diff --git a/tests/unit/expansion/expand.c b/tests/unit/expansion/expand.c
index 777083e..859256e 100644
--- a/tests/unit/expansion/expand.c
+++ b/tests/unit/expansion/expand.c
@@ -1,6 +1,7 @@
 #define _POSIX_C_SOURCE 200809L
 #include <criterion/criterion.h>
 #include <criterion/new/assert.h>
+#include <criterion/redirect.h>
 #include <stdlib.h>
 #include <unistd.h>
 
@@ -16,7 +17,7 @@ Test(expand, no_expansion)
     char str[] = "echo something";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     bool ret = expand(ast_command, NULL);
@@ -31,7 +32,7 @@ Test(expand, single_quotes_no_expansion)
     char str[] = "echo '$VAR'";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     struct hash_map *vars = vars_init();
@@ -50,7 +51,7 @@ Test(expand, single_dollar)
     char str[] = "echo $ sign";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     struct hash_map *vars = vars_init();
@@ -69,7 +70,7 @@ Test(expand, empty_braces_no_expansion)
     char str[] = "echo ${}";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     struct hash_map *vars = vars_init();
@@ -86,7 +87,7 @@ Test(expand, basic_expansion)
     char str[] = "echo $VAR";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     struct hash_map *vars = vars_init();
@@ -105,7 +106,7 @@ Test(expand, multiple_expansion)
     char str[] = "echo $VAR1 $VAR2 ${VAR3}";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     struct hash_map *vars = vars_init();
@@ -127,7 +128,7 @@ Test(expand, env_variable)
     char str[] = "echo $MY_ENV_VAR";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     setenv("MY_ENV_VAR", "environment", 0);
@@ -144,7 +145,7 @@ Test(expand, undefined_variable)
     char str[] = "echo $UNDEFINED";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     struct hash_map *vars = vars_init();
@@ -162,7 +163,7 @@ Test(expand, nested_expansion)
     char str[] = "echo $B";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     struct hash_map *vars = vars_init();
@@ -177,34 +178,34 @@ Test(expand, nested_expansion)
     hash_map_free(&vars);
 }
 
-// Test(expand, mixed_quotes_expansion)
-// {
-//     char str[] = "echo \"$VAR1 and '$VAR2'\"";
-//     char *str_heap = strdup(str);
-//     struct list *list = list_append(NULL, str_heap);
-//     struct ast *ast = ast_create_command(list, NULL, NULL);
-//     struct ast_command *ast_command = ast_get_command(ast);
+Test(expand, mixed_quotes_expansion)
+{
+    char str[] = "echo \"$VAR1 and '$VAR2'\"";
+    char *str_heap = strdup(str);
+    struct list *list = list_append(NULL, str_heap);
+    struct ast *ast = ast_create_command(list);
+    struct ast_command *ast_command = ast_get_command(ast);
 
-//     struct hash_map *vars = vars_init();
-//     set_var_copy(vars, "VAR1", "expanded");
-//     set_var_copy(vars, "VAR2", "not_expanded");
+    struct hash_map *vars = vars_init();
+    set_var_copy(vars, "VAR1", "expanded");
+    set_var_copy(vars, "VAR2", "not_expanded");
 
-//     bool ret = expand(ast_command, vars);
-//     cr_expect(ret, "expansion failed with %s", str);
-//     cr_expect_str_eq((char *)ast_command->command->data,
-//                      "echo \"expanded and $VAR2\"",
-//                      "Variable in double quotes should expand, while variable "
-//                      "in single quotes should not");
-//     ast_free(&ast);
-//     hash_map_free(&vars);
-// }
+    bool ret = expand(ast_command, vars);
+    cr_expect(ret, "expansion failed with %s", str);
+    cr_expect_str_eq((char *)ast_command->command->data,
+                     "echo \"expanded and $VAR2\"",
+                     "Variable in double quotes should expand, while variable "
+                     "in single quotes should not");
+    ast_free(&ast);
+    hash_map_free(&vars);
+}
 
 Test(expand, adjacent_variables)
 {
     char str[] = "echo $VAR1$VAR2";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     struct hash_map *vars = vars_init();
@@ -224,7 +225,7 @@ Test(expand, random)
     char str[] = "$RANDOM";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     bool ret = expand(ast_command, NULL);
@@ -240,7 +241,7 @@ Test(expand, pid)
     char str[] = "$$";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     struct hash_map *vars = vars_init();
@@ -258,7 +259,7 @@ Test(expand, default_last_exit_code)
     char str[] = "$?";
     char *str_heap = strdup(str);
     struct list *list = list_append(NULL, str_heap);
-    struct ast *ast = ast_create_command(list, NULL, NULL);
+    struct ast *ast = ast_create_command(list);
     struct ast_command *ast_command = ast_get_command(ast);
 
     struct hash_map *vars = vars_init();
diff --git a/tests/unit/expansion/parse_subshell.c b/tests/unit/expansion/parse_subshell.c
deleted file mode 100644
index 34ada43..0000000
--- a/tests/unit/expansion/parse_subshell.c
+++ /dev/null
@@ -1,72 +0,0 @@
-#include <criterion/criterion.h>
-#include <criterion/new/assert.h>
-
-#include "../../../src/expansion/expansion.h"
-
-TestSuite(parse_subshell_str);
-
-Test(parse_subshell_str, basic_subshell)
-{
-    char *input = "(ls -l)";
-    char *extracted_var = NULL;
-    size_t r = parse_subshell_str(input, &extracted_var);
-
-    cr_expect(r == 7);
-    cr_expect_str_eq(extracted_var, "ls -l");
-    free(extracted_var);
-}
-
-Test(parse_subshell_str, multi_basic_subshell)
-{
-    char *input = "(echo hello) and (echo world)";
-    char *extracted_var = NULL;
-    size_t r = parse_subshell_str(input, &extracted_var);
-
-    cr_expect(r == 12);
-    cr_expect_str_eq(extracted_var, "echo hello");
-    free(extracted_var);
-
-    input += r + 5; // skip " and "
-    r = parse_subshell_str(input, &extracted_var);
-
-    cr_expect(r == 12);
-    cr_expect_str_eq(extracted_var, "echo world");
-    free(extracted_var);
-}
-
-Test(parse_subshell_str, incomplete_braces)
-{
-    char *input = "(echo hello";
-    char *extracted_var = NULL;
-    size_t r = parse_subshell_str(input, &extracted_var);
-
-    cr_expect(r == 0);
-    cr_expect(extracted_var == NULL);
-}
-
-Test(parse_subshell_str, empty_braces)
-{
-    char *input = "()";
-    char *extracted_var = NULL;
-    size_t r = parse_subshell_str(input, &extracted_var);
-
-    cr_expect(r == 0);
-    cr_expect(extracted_var == NULL);
-}
-
-Test(parse_subshell_str, nested_subshell)
-{
-    char *input = "(echo (nested))";
-    char *extracted_var = NULL;
-    size_t r = parse_subshell_str(input, &extracted_var);
-
-    cr_expect(r == 15);
-    cr_expect_str_eq(extracted_var, "echo (nested)");
-    free(extracted_var);
-
-    char *nested = input + 6; // point to the nested subshell
-    r = parse_subshell_str(nested, &extracted_var);
-    cr_expect(r == 8);
-    cr_expect_str_eq(extracted_var, "nested");
-    free(extracted_var);
-}
diff --git a/tests/unit/expansion/parse_var.c b/tests/unit/expansion/parse_var.c
index 4dc9e08..27a4b94 100644
--- a/tests/unit/expansion/parse_var.c
+++ b/tests/unit/expansion/parse_var.c
@@ -1,5 +1,6 @@
 #include <criterion/criterion.h>
 #include <criterion/new/assert.h>
+#include <criterion/redirect.h>
 
 #include "../../../src/expansion/expansion.h"