feat: implemented pipes and redirects + background operator

shell.c

@@ -123,6 +123,9 @@ bool _parsePipeline(List *lp) {
  * @return a bool denoting whether the filename was parsed successfully.
  */
 bool _parseFilename(List *lp) {
+  if (*lp == NULL) return false;
+
+
   //we run a POSIX compliant system, meaning all characters save '/' and NULL are allowed in filenames. 
   //NULL is already taken care of by the List library, and / just means the file is located in a directory.
   //as a result the only limit we place on filenames are the reserved (operator) characters.
@@ -178,11 +181,9 @@ bool _parseBuiltIn(List *lp) {
     char *builtIns[] = {
             "exit",
             "status",
-            "true",
-            "false",
+            "cd",
         #if EXT_PROMPT
             "debug",
-            "cd",
         #endif
             NULL
     };