What problems does parsing cause?

Commmand-line parsing is inconsistent and error-prone.

Is -ab the same as -a -b?

Is -a -b the same as -b -a?

Also, security and virtualization:

• Child process needs same filesystem view as parent
• Child process needs permissions of parent
• Child process hard-codes how to turn strings into streams

We can sandbox child processes, but we often don't.