Todo.txt

To-Do
=====

- Handle input redirection
- Handle output redirection


Notes
=====
From Ian:
1) After looking at how we were handling background process reaping, I found that we were doing it wrong
and that no reaping actually took place. Load the version of shellex.c and csapp.c that Dennis
committed on 4/22/15 @ 10:55AM called with the comment "Add csapp.c". Then compile and run the shell.
Now enter any non-built-in command (like test.c that I committed with this) without the & argument.
The process will finish, and after waiting for a few seconds to assure the child process that the
command was running finishes press control-z to send the SIGTSTP command and stop (but not kill) the shell
process. Now enter the ps command. There will be the shell running-- all is well. Enter kill <pid> to kill
the command. Now run the shell again, but run the same command with the & argument to run the process in
the background. Wait a few seconds for the process to finish, and then press control-z again. Now enter
ps to see the processes. You will see that there is a child process that is a zombie which should be
denoted by <defunct> (on my Mac it was in parenthesis instead). The code we had up to this commit doesn't
reap background processes correctly.

2) After changing the code to start using a signal handler, the code may or may not reap the child background
process. The signal handler is called, but an error occurs and ends the shell process. I'm not sure if
the child process is reaped by the signal handler and then an error occurs and exits, or if the child process
is reaped by the system upon the failure of the shell (which would reap all zombie child processes).

The error is "waitpid error: Undefined error: 0"


- Reset redirection IO for next command