Re: "echo $((0x))" is accepted, treated as 0x0

On 1/24/26 10:23, Martin D Kealey wrote:
> On Sat, 24 Jan 2026 at 12:10, Denys Vlasenko <[email protected]> wrote:
> 
>> Subject: "echo $((0x))" is accepted, treated as 0x0
>> The subject says it all.
> 
> 
> Working as intended and as documented.
> 
> This is so that "echo $((0x$foo))" works as intended when foo contains only
> hexadecimal digits. Note that the empty string complies with that
> requirement.

Got it.

$ digits=''; echo $((0x$digits))
0

But why it's different for

$ digits=''; echo $((16#$digits))
bash: 16#: invalid integer constant (error token is "16#")