Re: [Help-bash] Is the usage " address@hidden:3:$i}" documented

[Greg Wooledge]

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.  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.
           ...