diff --git a/src/system/linux/alloc.c b/src/system/linux/alloc.c
index 69d497c..1c98631 100644
--- a/src/system/linux/alloc.c
+++ b/src/system/linux/alloc.c
@@ -107,6 +107,9 @@ void *msh_allocate(SIZE_TYPE size) {
 };
 
 void msh_deallocate(void *ptr) {
+  if (ptr == 0) {
+    return;
+  }
   msh_linux_block *block = get_metadata_block(ptr);
   block->free = 1;
   if (block->prev && block->prev->free) {
diff --git a/src/system/linux/env.c b/src/system/linux/env.c
index 22c072c..67d0c03 100644
--- a/src/system/linux/env.c
+++ b/src/system/linux/env.c
@@ -5,9 +5,9 @@ msh_linux_env_item *env_items = 0;
 msh_linux_env_item *env_item_tail = 0;
 
 void msh_linux_env_map_init() {
-  msh_file *env_file;
-  SIZE_TYPE cur;
-  char *file_buf;
+  msh_file *env_file = 0;
+  SIZE_TYPE cur = 0;
+  char *file_buf = 0;
   char ch = 1;
   int counter = 0, i = 0;
 
diff --git a/src/system/linux/linux.c b/src/system/linux/linux.c
index 287a6db..5c9537f 100644
--- a/src/system/linux/linux.c
+++ b/src/system/linux/linux.c
@@ -33,7 +33,6 @@ int msh_execute(char *cmd, char **args) {
     return 0;
   }
   SIZE_TYPE fork = (SIZE_TYPE)SYSCALL(fork, 0);
-  // int fork = 0;
 
   if (fork == 0) {
     char **env_translated = 0;
@@ -52,7 +51,8 @@ int msh_execute(char *cmd, char **args) {
         int n = 0;
         char *entry =
             msh_allocate(item_list->key_len + item_list->value_len + 2);
-        msh_str_copy_strs(entry, item_list->key, "=", item_list->value, "\0");
+        msh_str_copy_strs(entry, item_list->key, "=", item_list->value, "\0",
+                          0);
         env_translated[i++] = entry;
       }
       item_list = item_list->next;
@@ -99,10 +99,10 @@ msh_file *msh_file_open(const char *file) {
   return f;
 };
 
-void msh_file_close(msh_file *file) { 
-    SYSCALL(close, file->fd);
+void msh_file_close(msh_file *file) {
+  SYSCALL(close, file->fd);
 
-    msh_deallocate(file);
+  msh_deallocate(file);
 };
 
 void msh_file_read(msh_file *file, char *ptr, SIZE_TYPE n) {