http://www.davidpashley.com/articles/writing-robust-shell-scripts/
- How can you tell bash to exit when a variable is unitialised?
- How can you tell bash to exit when a command fails?
- How can you execute a command that fails in that scenario?
- How can you tell bash to exit when a pipe command fails?
- How do you create a directory?
- How do you delete a file?