Todo

• Subshell
  • Backtick subshell
  • Dollar sign subshell
• Pipelines
  • better pipelines that don't require EOF
• Basic single quote strings
• Double quote strings with substitutions
• Environment handling
  • Calling variables
  • Assigning Variables
  • Return values with $?
• Control Flow
  • if
  • elif
  • else
  • while
  • for
• Lists
  • And-if (||)
  • Or-if (&&)
• Background process control
  • Moving jobs to the background
  • bringing jobs to the foreground
  • listing available jobs
• essential built-ins
  • list of posix built ins at the bottom
  • cd
  • exit
  • true/false
  • alias
• ctrl-c to kill jobs
  • fix bug where ctrl-c on a job that modifies TTY state utterly breaks the terminal (for example less)
  • fix bug where ctrl-c kills bg jobs as well
  • Use libc calls directly (no ctrl-c rs crate)
  • jobs in array aren't removed when child ends
• Path cleaning w/ out clean-path library
• Built in functions