Re: PS0 issue with escape sequence

[Chet Ramey]

On 9/17/16 4:47 PM, Benoît Dejean wrote:
> On Sat, Sep 17, 2016 at 01:12:24PM -0400, Chet Ramey wrote:
>> On 9/16/16 9:25 PM, Ben wrote:
>>> Hello,
>>>
>>> using bash-4.4, setting PS0 to '\[\033[1;36m\]started at
>>> \t\[\033[0m\]\n' makes it output PS0 with a non-printable \x01\x02
>>> prefix and suffix.
>>
>> Yes, those are the expansions of the \[ and \] escape sequences.  Since
>> $PS0 is not being passed to readline for display, you probably don't need
>> to include those escape sequences at all.
> 
> Would you consider enabling it ? The usage is obvious: display time of
> start and end of a command, with a different color/etc.

I think you misunderstood what I meant.  The reason to include the \[ and
\] escape sequences is so readline knows that the enclosed characters don't
display on the screen.  Since PS0 is not expanded or used by readline (the
usual set of escape sequences gets expanded and the result is printed with
fprintf()), you can include the color sequences without worrying about
needing \[ and \].

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/