On 25 Mar, 14:03, Stephane CHAZELAS <this.addr...@is.invalid> wrote:
> 2008-03-25, 06:53(-07), Spiros Bousbouras:
> [...]
>
> >> Only '\a', '\b', '\f', '\n', '\r', '\t', '\v' are standard.
>
> > That's what I thought but can an implementation
> > output anything it wants with \e or is there a collection
> > of permitted behaviours ?
>
> \e is unspecified. If you want to output \e as opposed to the
> ESC character, use printf '\\e' or printf %s '\e'

What does unspecified mean in POSIX ? In the C standard
it means that the standard specifies a list of behaviours
and the implementation can choose any one of them without
needing to document it.