"history" modifier question

"history" modifier question

[Jim]

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Hello,

Trying to use history modifier 'h [ digit ]' (the following also applies to
't [digit ]'),where digit is a scalar or integer, ( e.g. ${PWD:h${N}} ) to
step
through a path via a loop, but this doesn't appear to be allowed. Tried
multiple ways of doing this including quoting.

This seems like a logical use of a parameter, but 'my' logic, sometimes,
doesn't match reality.

Is there a way of doing this or is this just not possible. If not could
someone
tell me why, I would like to understand what I'm missing here. The man
page, AFAICT, doesn't say  one way or the other if this is possible. Unless,
"digit" is explicit here.

FYI, I did come up with an alternative method by using an array and split.

ZSH_VERSION: 5.9

Thanks for your time, and with regards,

Jim Murphy

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Re: "history" modifier question

[Bart Schaefer]

On Wed, May 3, 2023 at 11:32 PM Jim <linux.tech.guy@gmail.com> wrote:
>
> Trying to use history modifier 'h [ digit ]' (the following also applies to
> 't [digit ]'),where digit is a scalar or integer, ( e.g. ${PWD:h${N}} )

You can do it like this:  ${(e):-\${PWD:h${N}}}

> I would like to understand what I'm missing here. The man
> page, AFAICT, doesn't say  one way or the other if this is possible. Unless,
> "digit" is explicit here.

Yes, the digit following :h has to be a literal digit, not an expansion.

Re: "history" modifier question

[Jim]

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On Thu, May 4, 2023 at 7:19 PM Bart Schaefer <schaefer@brasslantern.com>
wrote:

>
> You can do it like this:  ${(e):-\${PWD:h${N}}}
>
> Yes that works, Thanks.
    e Perform single word shell expansions,
Had to think about that for a second, but got it. Learned my something new
for
today. :-)

Yes, the digit following :h has to be a literal digit, not an expansion.
>

Darn, it would have been nice, but your example is just fine.

Regards,

Jim Murphy

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