Re: Crash on large brace expansion

[Léa Gris]

Le 15/07/2021 à 21:23, Greg Wooledge écrivait :
> On Thu, Jul 15, 2021 at 05:28:04PM +0200, Léa Gris wrote:
> > Le 15/07/2021 à 16:36, Gabríel Arthúr Pétursson écrivait :
> > > Hi all,
> > >
> > > Executing the following results in a fierce crash:
> > >
> > >      $ bash -c '{0..255}.{0..255}.{0..255}.{0..255}'
> >
> > Brace expression expands all the value in memory.
> >
> > Here you are actually telling Bash to expand 256⁴ or 4294967296 42 Billion
> > entries.
>
> 4.2 billion, but who's counting? :-)

Ah yes, my billions or off by ten folds.

Here is a single-loop version to absolve me of my arithmetical 
overstatement:

a=0
while [ $a -lt 4294967296 ]; do
  printf '%d.%d.%d.%d\n' \
    $((a >> 24)) $((a >> 16 & 255)) $((a >> 8 & 255)) $((a & 255))
  a=$((a + 1))
done



--
Léa Gris