On 10/27/15 5:02 PM, Greg Wooledge wrote:
> I decided to play around with the ${var@P} expansion in 4.4-beta.
>
> imadev:~$ red=$(tput setaf 1) reset=$(tput sgr0)
> x='\[$red\]\u\[$reset\]@\h:\w\$ '; printf %s "${x@P}" | od -t x1
> 0000000 1 1b 5b 33 31 6d 2 77 6f 6f 6c 65 64 67 1 1b
> 0000020 5b 6d f 2 40 69 6d 61 64 65 76 3a 7e 24 20
> 0000037
>
> I don't think the "1" and "2" bytes should be printed. They're for
> internal use only, even if they're usually invisible.
That's what the \[ and \] escape sequences expand to and use to
communicate information to readline about invisible characters in the
prompt (RL_PROMPT_START_IGNORE and RL_PROMPT_END_IGNORE). If you want to
use the expansion of ${var@P} as, for instance, the prompt passed to
readline when using `read -e -p prompt', those characters need to be there.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU c...@case.edu http://cnswww.cns.cwru.edu/~chet/
