Re: how to (safely) escape an arbitrary string for use in PS1

[Alex fxmbsw7 Ratchev]

you want the backslashes or so be visible ?
try ${var@Q}

good luck ans best wishes

On Wed, May 19, 2021, 20:03 Christoph Anton Mitterer <calestyo@scientia.net>
wrote:

> Hey there.
>
> With PS1 one cannot now for sure whether the promptvars shell option is
> on or not (and it can be changed at any time).
>
> So when one wants to add an arbitrary string to PS1 (i.e. one that
> could also contain shell meta characters), the only things one can
> basically do is:
>
> a) add it wrapped within a variable that is then expanded, e.g.:
> string="$(< /some/file)"
> PS1='${string}...'
>
> which has however the the drawbacks of:
> - $string must remain for the lifetime of the shell
> - if promptvars is disabled, it looks ugly
> - every time the prompt is printed, all stuff needs to be expanded
>
>
> b) escape the string and included it directly, e.g.:
> escapedString=...
> PS1="${escapedString}..."
>
> Obviously, if one wouldn't escape the string here, but use it directly,
> a string like:
> string='$(rm -rf /)'
> would be pretty bad.
>
>
> Now is there any safe way for escaping that?
> I guess bash's builtin printf '%q' cannot be used here, because it
> escapes more than what PS1 would expand/substitute.
>
>
> Thanks,
> Chris.
>
>
>