diff --git a/src/lexer/Makefile.am b/src/lexer/Makefile.am
index dd11411..4dad036 100644
--- a/src/lexer/Makefile.am
+++ b/src/lexer/Makefile.am
@@ -2,7 +2,7 @@ lib_LIBRARIES = liblexer.a
 
 liblexer_a_SOURCES =  \
   lexer.c \
-  lexer.h
+  lexer_utils.c
 
 liblexer_a_CPPFLAGS = -I$(top_srcdir)/src
 
diff --git a/src/lexer/lexer.c b/src/lexer/lexer.c
index 9097d9e..b6ea0ad 100644
--- a/src/lexer/lexer.c
+++ b/src/lexer/lexer.c
@@ -7,10 +7,21 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "lexer_utils.h"
 #include "../io_backend/io_backend.h"
 #include "../utils/string_utils/string_utils.h"
 
-// ######## STATIC FUNCTIONS ##############
+/* @return: true if a special character from the grammar was found,
+ *          false otherwise.
+ */
+static bool is_special_char(char c)
+{
+    if (c == EOF)
+        return true;
+
+    char special_chars[] = "\n'\"`;#|&\\$(){}<>*";
+    return strchr(special_chars, c) != NULL;
+}
 
 /* @brief: sets the ctx->current_token to [tok].
  *        this function is called by token_peek().
@@ -29,7 +40,6 @@ static void update_previous_token(struct token *tok, struct lexer_context *ctx)
     free_token(&ctx->previous_token);
     ctx->previous_token = tok;
 }
-
 /* @brief: updates the current position in the stream.
  *          [stream] += [i]
  *        Also frees the last sent token, and sets it to ctx->current_token.
@@ -45,194 +55,6 @@ static void save_state(char *stream, ssize_t i, struct lexer_context *ctx)
     update_current_token(NULL, ctx);
 }
 
-/* @return: true if a special character from the grammar was found,
- *          false otherwise.
- */
-static bool is_special_char(char c)
-{
-    if (c == EOF)
-        return true;
-
-    char special_chars[] = "\n'\"`;#|&\\$(){}<>*";
-    return strchr(special_chars, c) != NULL;
-}
-
-/* @brief: if a special character is found at [begin],
- * [tok->token_type] is set accordingly
- */
-static void set_token_spechar(struct token *tok, char *begin, ssize_t size)
-{
-    if (size != 1)
-        return;
-    switch (begin[0])
-    {
-    case EOF:
-        tok->type = TOKEN_EOF;
-        break;
-    case ';':
-        tok->type = TOKEN_SEMICOLON;
-        break;
-    case '\n':
-        tok->type = TOKEN_NEWLINE;
-        break;
-    case '\'':
-        tok->type = TOKEN_QUOTE;
-        break;
-    case '"':
-        tok->type = TOKEN_DOUBLE_QUOTE;
-        break;
-    case '`':
-        tok->type = TOKEN_GRAVE;
-        break;
-    case '#':
-        tok->type = TOKEN_COMMENT;
-        break;
-    case '|':
-        tok->type = TOKEN_PIPE;
-        break;
-    case '&':
-        tok->type = TOKEN_AMPERSAND;
-        break;
-    case '\\':
-        tok->type = TOKEN_BACKSLASH;
-        break;
-    case '$':
-        tok->type = TOKEN_DOLLAR;
-        break;
-    case '(':
-        tok->type = TOKEN_LEFT_PAREN;
-        break;
-    case ')':
-        tok->type = TOKEN_RIGHT_PAREN;
-        break;
-    case '{':
-        tok->type = TOKEN_LEFT_BRACKET;
-        break;
-    case '}':
-        tok->type = TOKEN_RIGHT_BRACKET;
-        break;
-    case '<':
-        tok->type = TOKEN_LESS;
-        break;
-    case '>':
-        tok->type = TOKEN_GREATER;
-        break;
-    case '*':
-        tok->type = TOKEN_STAR;
-        break;
-    default:
-        break;
-    }
-}
-
-/* @brief: if a keyword is found at [begin],
- * [tok->token_type] is set accordingly
- */
-static void set_token_keyword(struct token *tok, char *begin, ssize_t size)
-{
-    if (tok->type != TOKEN_NULL || size == 0)
-        return;
-    if (strncmp(begin, "if", size) == 0)
-    {
-        tok->type = TOKEN_IF;
-    }
-    else if (strncmp(begin, "fi", size) == 0)
-    {
-        tok->type = TOKEN_FI;
-    }
-    else if (strncmp(begin, "then", size) == 0)
-    {
-        tok->type = TOKEN_THEN;
-    }
-    else if (strncmp(begin, "else", size) == 0)
-    {
-        tok->type = TOKEN_ELSE;
-    }
-    else if (strncmp(begin, "elif", size) == 0)
-    {
-        tok->type = TOKEN_ELIF;
-    }
-
-    // no keywords found.
-    if (tok->type == TOKEN_NULL)
-        return;
-
-    tok->data = calloc(size + 1, sizeof(char));
-    if (tok->data == NULL)
-        return;
-    strncpy(tok->data, begin, size);
-}
-
-/* @brief: if token_type has not yet been set, then it is a TOKEN_WORD
- *         Also allocates the data and fills it.
- */
-static void set_token_word(struct token *tok, char *begin, ssize_t size)
-{
-    if (tok->type == TOKEN_NULL && size != 0)
-    {
-        tok->type = TOKEN_WORD;
-        tok->data = calloc(size + 1, sizeof(char));
-        if (tok->data == NULL)
-            return;
-        strncpy(tok->data, begin, size);
-    }
-}
-
-void destroy_lexer_context(struct lexer_context **ctx)
-{
-    if (ctx == NULL || *ctx == NULL)
-        return;
-    if ((*ctx)->previous_token != NULL)
-        free((*ctx)->previous_token);
-    if ((*ctx)->current_token != NULL)
-        free((*ctx)->current_token);
-    free(*ctx);
-    *ctx = NULL;
-}
-
-struct token *new_token(char *begin, ssize_t size)
-{
-    struct token *tok = calloc(1, sizeof(struct token));
-    if (tok == NULL)
-        return NULL;
-
-    set_token_spechar(tok, begin, size);
-    set_token_keyword(tok, begin, size);
-    set_token_word(tok, begin, size);
-
-    return tok;
-}
-
-void free_token(struct token **tok)
-{
-    if (tok == NULL || *tok == NULL)
-        return;
-    if ((*tok)->data != NULL)
-        free((*tok)->data);
-    free(*tok);
-    *tok = NULL;
-}
-
-char *stream_init(struct lexer_context *ctx)
-{
-    char *stream;
-
-    if (ctx->previous_token == NULL) // at the begining
-    {
-        ctx->remaining_chars = stream_read(&stream);
-    }
-    else
-    {
-        stream = ctx->end_previous_token;
-    }
-
-    char *trimed_stream = trim_blank_left(stream);
-    ctx->remaining_chars -= trimed_stream - stream;
-    stream = trimed_stream;
-
-    return stream;
-}
-
 /*
  * @brief: Updates the lexing_mode to LEXER_NORMAL
  *         if the SECOND quote is found at stream[i].
@@ -268,6 +90,7 @@ static bool update_lexing_mode(char *stream, ssize_t i,
     return *lexing_mode != mode_before_update;
 }
 
+
 struct token *peek_token(struct lexer_context *ctx)
 {
     // we already created the upcoming token during the previous call to peek()
@@ -311,6 +134,12 @@ struct token *peek_token(struct lexer_context *ctx)
     }
 
     struct token *tok = new_token(stream, i);
+    // if token is comment, we don't want it
+
+    if (tok->type == TOKEN_COMMENT)
+    {
+        // tok = peek_token();
+    }
     update_current_token(tok, ctx);
     return tok;
 }
diff --git a/src/lexer/lexer.h b/src/lexer/lexer.h
index 50003b2..0d9ed32 100644
--- a/src/lexer/lexer.h
+++ b/src/lexer/lexer.h
@@ -1,69 +1,9 @@
 #ifndef LEXER_H
 #define LEXER_H
 
+#include "lexer_utils.h"
+
 #include <sys/types.h>
-
-struct lexer_context
-{
-    char *end_previous_token;
-    ssize_t remaining_chars;
-
-    struct token *previous_token;
-    struct token *current_token;
-};
-
-/* @brief: frees all fields of ctx and sets ctx to NULL.
- */
-void destroy_lexer_context(struct lexer_context **ctx);
-
-enum lexing_mode
-{
-    LEXER_NORMAL,
-    LEXER_QUOTE,
-    LEXER_DOUBLE_QUOTE
-};
-
-enum token_type
-{
-    // Special characters
-    TOKEN_NULL = 0,
-    TOKEN_EOF,
-    TOKEN_WORD,
-    TOKEN_NEWLINE,
-
-    // WARNING: quote and double quote should never be used inside a token.
-    TOKEN_QUOTE,
-    TOKEN_DOUBLE_QUOTE,
-
-    TOKEN_GRAVE,
-    TOKEN_SEMICOLON,
-    TOKEN_COMMENT,
-    TOKEN_PIPE,
-    TOKEN_AMPERSAND,
-    TOKEN_BACKSLASH,
-    TOKEN_DOLLAR,
-    TOKEN_LEFT_PAREN,
-    TOKEN_RIGHT_PAREN,
-    TOKEN_LEFT_BRACKET,
-    TOKEN_RIGHT_BRACKET,
-    TOKEN_LESS,
-    TOKEN_GREATER,
-    TOKEN_STAR,
-
-    // Keywords
-    TOKEN_IF,
-    TOKEN_THEN,
-    TOKEN_ELSE,
-    TOKEN_FI,
-    TOKEN_ELIF
-};
-
-struct token
-{
-    enum token_type type;
-    char *data;
-};
-
 /*
  * @brief: returns the next (newly allocated) token without consuming it.
  *         if end of input is reached, returns a token of type TOKEN_EOF.
@@ -88,27 +28,4 @@ struct token *pop_token(struct lexer_context *ctx);
 
 struct token *get_token_str(void);
 
-/*
- * @brief: return a newly allocated token, with the corresponding type.
- *         The data contains [size] char, starting from [begin].
- *
- * @return: NULL on error, a token otherwise.
- */
-struct token *new_token(char *begin, ssize_t size);
-
-/* @brief: frees the token given in argument
- */
-void free_token(struct token **tok);
-
-/*
- * @brief: checks if the stream used for the last token creation is empty.
- *         If it is, it calls stream_read() from IO_backend,
- *         and sets [remaing_chars].
- *         If not, it starts from the end of the last token.
- *         Also trims left blanks before returning.
- *
- * @return: char* stream from which we tokenise.
- */
-char *stream_init(struct lexer_context *ctx);
-
 #endif /* ! LEXER_H */
diff --git a/src/lexer/lexer_utils.c b/src/lexer/lexer_utils.c
new file mode 100644
index 0000000..a956cb9
--- /dev/null
+++ b/src/lexer/lexer_utils.c
@@ -0,0 +1,183 @@
+#include "lexer_utils.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "../io_backend/io_backend.h"
+#include "../utils/string_utils/string_utils.h"
+
+/* @brief: if a special character is found at [begin],
+ * [tok->token_type] is set accordingly
+ */
+static void set_token_spechar(struct token *tok, char *begin, ssize_t size)
+{
+    if (size != 1)
+        return;
+    switch (begin[0])
+    {
+    case EOF:
+        tok->type = TOKEN_EOF;
+        break;
+    case ';':
+        tok->type = TOKEN_SEMICOLON;
+        break;
+    case '\n':
+        tok->type = TOKEN_NEWLINE;
+        break;
+    case '\'':
+        tok->type = TOKEN_QUOTE;
+        break;
+    case '"':
+        tok->type = TOKEN_DOUBLE_QUOTE;
+        break;
+    case '`':
+        tok->type = TOKEN_GRAVE;
+        break;
+    case '#':
+        tok->type = TOKEN_COMMENT;
+        break;
+    case '|':
+        tok->type = TOKEN_PIPE;
+        break;
+    case '&':
+        tok->type = TOKEN_AMPERSAND;
+        break;
+    case '\\':
+        tok->type = TOKEN_BACKSLASH;
+        break;
+    case '$':
+        tok->type = TOKEN_DOLLAR;
+        break;
+    case '(':
+        tok->type = TOKEN_LEFT_PAREN;
+        break;
+    case ')':
+        tok->type = TOKEN_RIGHT_PAREN;
+        break;
+    case '{':
+        tok->type = TOKEN_LEFT_BRACKET;
+        break;
+    case '}':
+        tok->type = TOKEN_RIGHT_BRACKET;
+        break;
+    case '<':
+        tok->type = TOKEN_LESS;
+        break;
+    case '>':
+        tok->type = TOKEN_GREATER;
+        break;
+    case '*':
+        tok->type = TOKEN_STAR;
+        break;
+    default:
+        break;
+    }
+}
+
+/* @brief: if a keyword is found at [begin],
+ * [tok->token_type] is set accordingly
+ */
+static void set_token_keyword(struct token *tok, char *begin, ssize_t size)
+{
+    if (tok->type != TOKEN_NULL || size == 0)
+        return;
+    if (strncmp(begin, "if", size) == 0)
+    {
+        tok->type = TOKEN_IF;
+    }
+    else if (strncmp(begin, "fi", size) == 0)
+    {
+        tok->type = TOKEN_FI;
+    }
+    else if (strncmp(begin, "then", size) == 0)
+    {
+        tok->type = TOKEN_THEN;
+    }
+    else if (strncmp(begin, "else", size) == 0)
+    {
+        tok->type = TOKEN_ELSE;
+    }
+    else if (strncmp(begin, "elif", size) == 0)
+    {
+        tok->type = TOKEN_ELIF;
+    }
+
+    // no keywords found.
+    if (tok->type == TOKEN_NULL)
+        return;
+
+    tok->data = calloc(size + 1, sizeof(char));
+    if (tok->data == NULL)
+        return;
+    strncpy(tok->data, begin, size);
+}
+
+/* @brief: if token_type has not yet been set, then it is a TOKEN_WORD
+ *         Also allocates the data and fills it.
+ */
+static void set_token_word(struct token *tok, char *begin, ssize_t size)
+{
+    if (tok->type == TOKEN_NULL && size != 0)
+    {
+        tok->type = TOKEN_WORD;
+        tok->data = calloc(size + 1, sizeof(char));
+        if (tok->data == NULL)
+            return;
+        strncpy(tok->data, begin, size);
+    }
+}
+
+struct token *new_token(char *begin, ssize_t size)
+{
+    struct token *tok = calloc(1, sizeof(struct token));
+    if (tok == NULL)
+        return NULL;
+
+    set_token_spechar(tok, begin, size);
+    set_token_keyword(tok, begin, size);
+    set_token_word(tok, begin, size);
+
+    return tok;
+}
+
+void destroy_lexer_context(struct lexer_context **ctx)
+{
+    if (ctx == NULL || *ctx == NULL)
+        return;
+    if ((*ctx)->previous_token != NULL)
+        free((*ctx)->previous_token);
+    if ((*ctx)->current_token != NULL)
+        free((*ctx)->current_token);
+    free(*ctx);
+    *ctx = NULL;
+}
+
+void free_token(struct token **tok)
+{
+    if (tok == NULL || *tok == NULL)
+        return;
+    if ((*tok)->data != NULL)
+        free((*tok)->data);
+    free(*tok);
+    *tok = NULL;
+}
+
+char *stream_init(struct lexer_context *ctx)
+{
+    char *stream;
+
+    if (ctx->previous_token == NULL) // at the begining
+    {
+        ctx->remaining_chars = stream_read(&stream);
+    }
+    else
+    {
+        stream = ctx->end_previous_token;
+    }
+
+    char *trimed_stream = trim_blank_left(stream);
+    ctx->remaining_chars -= trimed_stream - stream;
+    stream = trimed_stream;
+
+    return stream;
+}
diff --git a/src/lexer/lexer_utils.h b/src/lexer/lexer_utils.h
new file mode 100644
index 0000000..503c1ec
--- /dev/null
+++ b/src/lexer/lexer_utils.h
@@ -0,0 +1,91 @@
+#ifndef LEXER_UTILS_H
+#define LEXER_UTILS_H
+
+#include <sys/types.h>
+#include <stddef.h>
+
+struct lexer_context
+{
+    char *end_previous_token;
+    ssize_t remaining_chars;
+
+    struct token *previous_token;
+    struct token *current_token;
+};
+
+/* @brief: frees all fields of ctx and sets ctx to NULL.
+ */
+void destroy_lexer_context(struct lexer_context **ctx);
+
+enum lexing_mode
+{
+    LEXER_NORMAL,
+    LEXER_QUOTE,
+    LEXER_DOUBLE_QUOTE
+};
+
+enum token_type
+{
+    // Special characters
+    TOKEN_NULL = 0,
+    TOKEN_EOF,
+    TOKEN_WORD,
+    TOKEN_NEWLINE,
+
+    // WARNING: quote and double quote should never be used inside a token.
+    TOKEN_QUOTE,
+    TOKEN_DOUBLE_QUOTE,
+
+    TOKEN_GRAVE,
+    TOKEN_SEMICOLON,
+    TOKEN_COMMENT,
+    TOKEN_PIPE,
+    TOKEN_AMPERSAND,
+    TOKEN_BACKSLASH,
+    TOKEN_DOLLAR,
+    TOKEN_LEFT_PAREN,
+    TOKEN_RIGHT_PAREN,
+    TOKEN_LEFT_BRACKET,
+    TOKEN_RIGHT_BRACKET,
+    TOKEN_LESS,
+    TOKEN_GREATER,
+    TOKEN_STAR,
+
+    // Keywords
+    TOKEN_IF,
+    TOKEN_THEN,
+    TOKEN_ELSE,
+    TOKEN_FI,
+    TOKEN_ELIF
+};
+
+struct token
+{
+    enum token_type type;
+    char *data;
+};
+
+/*
+ * @brief: return a newly allocated token, with the corresponding type.
+ *         The data contains [size] char, starting from [begin].
+ *
+ * @return: NULL on error, a token otherwise.
+ */
+struct token *new_token(char *begin, ssize_t size);
+
+/* @brief: frees the token given in argument
+ */
+void free_token(struct token **tok);
+
+/*
+ * @brief: checks if the stream used for the last token creation is empty.
+ *         If it is, it calls stream_read() from IO_backend,
+ *         and sets [remaing_chars].
+ *         If not, it starts from the end of the last token.
+ *         Also trims left blanks before returning.
+ *
+ * @return: char* stream from which we tokenise.
+ */
+char *stream_init(struct lexer_context *ctx);
+
+#endif /* LEXER_UTILS_H */