Re: Antw: Re: `${PARAMETER:OFFSET}' does not work for negative offset

[Greg Wooledge]

On Fri, Feb 12, 2016 at 02:45:23PM +0100, Ulrich Windl wrote:
> I realized that ":-2" is ambiguous: Default value or substring? A SPC does 
> disambiguate (now I know). I still wonder why the manual page does not change 
> "${parameter:offset}" and "${parameter:offset:length}" to "${parameter: 
> offset}" and "${parameter: offset:length}", respectively. Or change the 
> wording of "If offset evaluates to a number less than  zero" to "If offset 
> evaluates to a number less than  zero AND begins with a space"

Gah, long lines.

The man page says:

           If offset evaluates to a number less than zero, the value is used
           as an offset in characters from the end of the value of
           parameter.  If length evaluates to a number less than zero, it is
           interpreted as an offset in characters from the end of the value
           of parameter rather than a number of characters, and the
           expansion is the characters between offset and that result.  Note
           that a negative offset must be separated from the colon by at
           least one space to avoid being confused with the :- expansion.

Either that last sentence wasn't present in the 4.2 man page, or you
simply missed it.