diff --git a/src/env/env.c b/src/env/env.c
index d935374..87b61bb 100644
--- a/src/env/env.c
+++ b/src/env/env.c
@@ -105,7 +105,7 @@ lst** env_init(const char** env)
 	return (root);
 }
 
-char *get_env_variable(lst** root, char* key)
+char *get_env_variable(lst** root, const char* key)
 {
 	lst* current = *root;
 	env *content;
diff --git a/src/env/env.h b/src/env/env.h
index 728f92c..1b5afcd 100644
--- a/src/env/env.h
+++ b/src/env/env.h
@@ -10,3 +10,4 @@ typedef struct s_env
 int add_env_variable(lst** root, const char *key, const char *value);
 lst** env_init(const char **env);
 void env_del(void *ptr);
+char *get_env_variable(lst** root, const char* key);