[GTALUG] Ubuntu (or debian): apt-get auto-remove?

[D. Hugh Redelmeier]

| From: Chris F.A. Johnson <chris at cfajohnson.com>

|     It only causes the shell to exit if a simple command fails.

Right.  That does create some surprises.  But these were all simple
commands.  And most of my errors are in simple commands.

|     Best practice is not to use it at all.
| 
|    <http://mywiki.wooledge.org/BashFAQ/105>

Thanks.  Useful.  I respectfully disagree with the conclusion.

| > "set -u" tells the shell to treat a reference to an undefined
| > parameter as an error.  It will make no difference in this script.
| > Until the script evolves more complexity.
| 
|    There's no point to using set -u after a script has been debugged.

The sad fact is that I don't know when I've gotten rid of the last bug
in a script.

It's really handy to have this on: I then know that most typos in
parameter names will be caught so when I have a bug, I don't have to
check for that kind of error myself and can concentrate on looking for
other pathologies.  Silently replacing a reference to a non-existent
parameter with nothing is just dumb human engineering.

I cannot find the Hoare quote that I'm looking for, but this seems to
be a mangled version of it:

	Once said that removing type checking from your running programs and
	using them only for testing is like wearing a life jacket on your
	practice emergency drills and taking them off as soon as your ship was
	really sinking.

<http://blog.mattcallanan.net/2010/09/tony-hoare-billion-dollar-mistake.html>

Another relevant quote:

	a programming language designer should be responsible for the
	mistakes that are made by the programmers using the language

(Hoare is a real great of our field.)