Re: Syntax Question...

[Linda Walsh]

` Dennis Williamson wrote:
> On Sun, Aug 14, 2011 at 6:31 PM, Linda Walsh <bash@tlinx.org> wrote:
>   
> > > > please show quote the section
> > > > that shows using an variable that holds the name of an array to be used
> > > > (and assigned to).... 
> > ====
> > The FAQ covers indirect,
> > it covers arrays,
> > but I see no place where it covers the combination.
> >     
----
   That's EXACTLY what I said -- it doesn't show anyway to do it, in fact,
it points the the exact problem I've been complaining about is bash's 
instability
in it's extended features.   I thought it would be like perl -- stable 
progression, not
random jumps that break code.

   All he's saying is bash "shouldn't" or "can't (with any stability), 
but used for
anything complex.

   He may be right.

   Personally I think it sucks.

   I was very happy with bash's extensions, and their progression -- 
right up to this
last revision, when functionality was removed, and others functionality 
was broken

-- I USE tabs when typing a program into bash -- not all the time, but
now I can't -- in "single quotes", it tries to expand to all the words 
in my curdir.

The script I've been working on was suppose to be relatively simple -- 
but given the all
the error checking I've been putting in, and all of the state tracking 
so a run of the script wouldn't come in and corrupt what had been left 
by a previous run, it's gotten ALOT more complex.

Conceptually...about 8-10 lines of english, -> almost 1500 lines of bash 
code -- MUCH of
which is to compensate for bashes new broken features.


One can claim it's my fault for not using POSIX, but I don't have this 
problem in perl (the python people did...)....  maybe I haven't 
appreciated how stable perl has been -- like C.

But
1) create snapshot
2) look for oldest active snapshot
3) rsync the diffs from the oldest snapshot compared against current to 
a 'diff vol'
4) create new 'static vol' sized to content on diff vol, and get rid of 
the oldest active snapshot.


That's. IT!

But...
.9) see if we have already created a snapshot today and require an 
override flag
3.5) label diff vol  with content label of snapshot this came from.
with labeled diff vol, can remove old active snapshot (which needs to be 
removed
before creating a new one w/same name & same mount point, but static)...
(could create new vol, and do renames, but would result in >lvm 
fragmentation).
2.8) before copying to diff dir -- make sure it is the correct mounted 
file system and
delete it's contents (dependent on there being a "valid snap copy"...)

which doesn't get set until the diff dir is copied to the new static 
stap and IT gets
a label -- saying that the diff-copy completed successfully.

etc.
etc.
etc...


It's just been growing...
(I didn't come close to listing all the checks that are in there now)...

So conceptually --- looked like a simple shell script.

but...to handle bash's broken error handling, all steps have to be 
'interlocked' --
state 'checked' into a file system, and validated before going to the 
next step.

Otherwise, I end up with more problems than you want to know about.

> Please try to be briefer and more on topic in your posts to this list,
> by the way.
>
>   

I'm stopping now.
Maybe not entirely on-topic, but I wasn't the one who started a side 
conversation by
claiming that the information I needed was on URLxxyz...when it wasn't.

It wasn't obvious from anyone that there was some subtle hint that 
trying to use
bash for things like this was ridiculous (if that's the message I was 
supposed to get
from reading it).    I may be tending more to to agree....but I honestly
thought bash seemed forwardly stable....with broken compat, being 
relegated to
--posix mode.   I'm slow to change when things 'break' -- I'd prefer to 
try to get them
fixed, or fix them, than move-on.   I know -- most people just move 
on...whatever.

Thanks for the clarification (I think?)...