Bash – $(( )) vs. $[]

[Gene Heskett]

On Wednesday 05 December 2012 16:14:25 Steve Flynn did opine:

> On 5 December 2012 19:54, Gene Heskett <gheskett at wdtv.com> wrote:
> > It may not be so 'user-friendly' but its the sharpest swiss army knife
> > we have.  Much of the automation in mail handling is from bash
> > scripts I wrote.
> 
> zsh for the win!
> 
> > Likewise, I am keeping a local repo for an legacy computer here, and
> > as I code its handy to have a printer for hard copies of my assembly
> > drivel.
> > 
> > There are NO printers for sale today that a TRS-80 Color Computer can
> > drive with its pure text listing output.  So I have a ser-usb on that
> > port, send it up the cable to this machine, which then feeds it thru
> > cups and back to a $110 B&W Brother laser printer on that machines
> > desk in the basement.
> > 
> > Its absolutely the best looking output that machine has ever had, and
> > at 22 pages a minute, easily 40x faster than its next best lashup,
> > which was a xerox 1650-ro, a 40 cps daisy wheel I can't get one time
> > ribbons for anymore, they are too old & shatter like glass on the
> > first hammer strike.
> > 
> > If I had to write all that in C and build it, I probably could, but
> > bash gets the job done while I am writing an outline framework for
> > the C version.  Maybe its slow, but slow is relative on a quad core
> > phenom. :)
> > 
> > The longest delay is the drum warmup in the printer, about 4 or 5
> > seconds. Whats not to like?
> 
> Eh? We're talking about shall A versus shell B. You're on about
> printers. Is there some connection I've missed?

No, I was just relating how easy it was to do with a bash script, running 
as a daemon on this machine.  The printer wasn't intended to be the star, 
the bash script that made it possible is the star.  Nowadays, there is a 
java .jar in series with the path the data travels and its about 15x 
faster, but the end result is the same.  Beautiful assembly language 
listing hardcopy.

Cheers, Gene
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