[Techtalk] Killing With Linux: A Primer

[mgmonza at sdf.lonestar.org]

Thanks, Val.

You've cleared up a decade-old "What the..?" for me.  I'd aliased 'y' to 
things like "Do you really want a screen full of yes's" (without, of 
course, outputting the "yes") for years before the ubiquitous -f, but 
always had that little question at the back of my mind.

Now I know.


Kathleen

  On Wed, 26 Apr 2006, Val Henson wrote:

> Date: Wed, 26 Apr 2006 14:39:26 -0700
> From: Val Henson <val.henson at gmail.com>
> To: techtalk at linuxchix.org
> Subject: Re: [Techtalk] Killing With Linux: A Primer
> 
> On 4/25/06, Carla Schroder <carla at bratgrrl.com> wrote:
>> On Tuesday 25 April 2006 8:15 pm, Val Henson wrote:
>>> This is probably also too basic for Techtalk, but the origin of the
>>> yes command is a funny story. Anyone feel like telling it?
>>
>> Well come on, someone must know this! I am dying of suspense.
>
> I've held back for several reasons:
>
> 1. Inability to find documentation (translation: I could be wrong).
> 2. Hope that someone else knows more than me.
> 3. Perhaps "funny" is too strong a word. :)
>
> So, back in the old days, some UNIX utilities wanted you to confirm
> that you really wanted to do something before it would actually do it.
> This is fine, except that sometimes it would ask you, literally,
> thousands of times, and, this being the old days, these commands
> tended not to have some command line option for "assume yes."
> Usually, the way you indicate the "yes" answer is by typing 'y' and
> then the Enter key.  Early UNIX admins would sometimes spend hours -
> yes, hours - hitting 'y', enter, 'y', enter..
>
> One of these annoying interactive applications is fsck, the file
> system checker.  When it is repairing a file system, by default it
> asks you to confirm many operations this way, because, you know, the
> person running it is highly likely to be a file systems expert and
> would be better off repairing the errors by hand.  Not.  One of the
> implications of this design was that if a system crashed, you had to
> run fsck before you could finish booting, and you might have to sit at
> a console and type 'y', enter, hundreds of times before the system was
> usable again.
>
> So the "yes" command was invented.  By default, it outputs "y",
> newline, "y", newline... You just hook this up to any annoying program
> that wants lots and lots of user interaction and voila, you get to
> rest your sore fingers while "yes" does the typing.
>
> $ yes | fsck /dev/whatever
> Deleted inode 180300 has zero dtime.  Fix? y
> Directories count wrong for group #11 (17, counted=15).
> Fix? y
> [...]
>
> But nowadays, most utilities (including fsck) are smart enough to
> include a command line option that says "Do it all automatically,
> don't bug me."
>
> YOU COULD HOSE YOUR SYSTEM WARNING: Don't go off and run any of these
> commands just for the fun of it; usually programs ask these questions
> for a good reason - because you might not want it do what it's about
> to do.
>
> I hope that was mildly entertaining, if not actually funny.
>
> -VAL
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