[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Help-bash] Is the usage " address@hidden:3:$i}" documented
From: |
Peng Yu |
Subject: |
Re: [Help-bash] Is the usage " address@hidden:3:$i}" documented |
Date: |
Wed, 1 Apr 2015 15:52:05 -0500 |
On Wed, Apr 1, 2015 at 3:48 PM, Greg Wooledge <address@hidden> wrote:
> On Wed, Apr 01, 2015 at 03:41:43PM -0500, Peng Yu wrote:
>> I use regex to search for ":.*:", but I only find
>> ${parameter:offset:length} in the manpage.
>>
>> Where is the usage of something like " address@hidden:3:$i}" documented?
>
> Read the section you already found.
>
> Parameter Expansion
> ...
> ${parameter:offset:length}
> Substring Expansion.
It would be better say here not only just Substring Expansion but also
array subsettng or something like. It is critically to have a topic
sentence when one writes for regular document. This principle should
applies to bash document as well.
http://examples.yourdictionary.com/examples-of-topic-sentences.html
> Expands to up to length characters of the
> value of parameter starting at the character specified by offset.
> ...
> If parameter is an indexed array name subscripted by @ or *, the
> result is the length members of the array beginning with
> ${parameter[offset]}. A negative offset is taken relative to one
> greater than the maximum index of the specified array. It is an
> expansion error if length evaluates to a number less than zero.
> ...
--
Regards,
Peng