bug#13525: 8.20 - [seq 1 3 1] treated as [seq 1 3]

[Pádraig Brady]

On 01/22/2013 12:28 PM, Bernhard Voelker wrote:
> On 01/22/2013 01:17 PM, Pádraig Brady wrote:
> > Updated patch attached.
>
> That one is looking good ... but while we're at it:
>
> Anyone tried this, i.e. a Zero as INCREMENT?
>
>    $ seq 1 0 2
>
> This is equal to `yes 0`. Well, this is probably a (not
> documented) feature, but in the following examples, the "1"
> should be printed only once, shouldn't it?
>
>    $ seq 1 0 1
>    $ seq 1 0.0 1
>
> (BTW: "seq 2 0 1" works, i.e. doesn't print anything.)

Yes I was wondering that myself.

Though I suppose that `seq 0 0 1` prints endlessly,
means that it's consistent that as long as start <= end
and step == 0, then start is printed endlessly.

Maybe we should special case to only print
the start value once if step = 0.
Maybe one could use a step of 0 to hack a
min/max function or something?

  min() { minv=$(seq "$1" 0 "$2"); : ${minv:="$2"}; echo $minv; }
  max() { minv=$(seq "$1" 0 "$2"); : ${maxv:="$1"}; echo $maxv; }

Though I'm stretching here as that could be done
(albeit with 3 processes) like:

  min() { printf '%s\n' "$@" | sort -rg | tail -n1; }
  max() { printf '%s\n' "$@" | sort -g | tail -n1; }

cheers,
Pádraig.