If you want to run some scripts and don't want to deal with copying it from Crouton or Crostini into Crosh after extracting, there are some ways to use the available tools to do everything purely in Crosh in Developer Mode.
CLI recovery.sh instead of GUI/Chrome App
If you need to make git commits you'll either need to dev_install (when they fix it) or use chromebrew.
Working with Chrx installed Linux on the host disk (working on adding external disk detection at some point).