Re:

[Greg Wooledge]

On Mon, Mar 22, 2021 at 09:50:06AM +0000, Budi wrote:
> in a function k() in  ~/.bashrc
> 
> k(){ unset u;h=0; o=(${h:+ ! -path "./*.txt"}) ;u=($u "${o[@]}"); c=(.
> -regextype posix-extended "${b[@]}" -print); find "${c[@]}"
>  }
> 
> in output set -x:
> 
> + unset u
> + h-0

This is clearly a falsehood.  You didn't paste the actual output.

> + o=(${h:+ ! -path "./*.txt"})
> + u=($u "${o[@]}")

Why have the unquoted $u here when you know the variable is unset?

> + c=(. -regextype posix-extended "${b[@]}" -print)

What's in the array "b"?  You never showed any such array.

> + find . -regextype posix-extended ' ! -path ./*.txt' -print
> find: paths must precede expression: ` ! -path ./*.txt'
> 
> Why and how to solve ?

I think your real question is this one -- why did the exclamation point
and the word -path and the word ./*.txt all get squashed together into
a single word, instead of being inserted as three separate words?

If you can simplify your code down to *just* that case, and if you can
show an actual reproducer for it, then we might try to reproduce it
ourselves.

As it is now, I don't trust what you've written here, because you clearly
haven't been honest about it, and you haven't shown the actual commands
you ran ("set -x output" of what??), let alone the actual output.