Re: [Help-bash] Expand a prompt string to calculate its length?

[Andy Chu]

The @P techniques works if you don't have color in your prompt.  If you
have colors I'm not sure there's a way to do it in general.

The \[ and \] escape codes in PS1 are used to compensate for color when
passing to GNU readline.  They get translated to \0x00 and \0x01 if I
remember correctly.  GNU readline also has to have a notion of the prompt
width.

Andy







On Wed, Jun 19, 2019 at 11:14 AM Greg Wooledge <address@hidden> wrote:

> On Wed, Jun 19, 2019 at 01:09:33PM -0500, Jesse Hathaway wrote:
> > Is there anyway to expand a partial prompt string to calculate its
> length?
>
> In bash 4.4 and above, yes.
>
> wooledg:~$ tmp=${PS1@P}; echo "<$PS1> <${#PS1}> <$tmp> <${#tmp}>"
> <\h:\w\$ > <8> <wooledg:~$ > <11>
>
> The @P parameter expansion is one of the new "Parameter transformation"
> options.
>
>