Re: Unexpected Quick Substitution in string literals

[Greg Wooledge]

On Thu, Dec 14, 2023 at 09:41:17AM +0530, Sundeep Agarwal wrote:
> Thanks for the correction on my second example. I had assumed ^ wasn't
> special inside double quotes since the documentation mentions only the !
> character for history expansion (
> https://www.gnu.org/software/bash/manual/bash.html#Double-Quotes).
> 
> However, no character should be treated specially inside single quotes,
> right?
> 
> $ echo 'fig
> ^mango'
> fig
> !!:s^mango

This one also depends on history expansion being active.

unicorn:~$ bash-5.2
unicorn:~$ set -H
unicorn:~$ echo 'fig
> ^mango'
fig
!!:s^mango
unicorn:~$ set +H
unicorn:~$ echo 'fig
> ^mango'
fig
^mango

Is that the correct behavior?  I have no idea.  I don't understand the
rationale behind this piece of histexpand *at all*, so I don't know
whether it's supposed to trigger inside single quotes.  Or even what
it's *doing*.

I turned off histexpand decades ago, and haven't missed it.  But that's
just me.