[TUHS] Use of "{}" in the Shell?

[Warner Losh via TUHS]

On Tue, Aug 4, 2026, 2:08 PM Warner Losh <imp at bsdimp.com> wrote:

>
>
> On Tue, Aug 4, 2026, 1:23 PM David Barto <barto at kdbarto.org> wrote:
>
>> Then why does
>> echo me; echo $$
>> ( echo parens ; echo $$ ; )
>> { echo brace; echo $$ ; }
>>
>> Always echo the same pid?
>>
>> me
>> 46999
>> parens
>> 46999
>> brace
>> 46999
>
>
> Because {} doesn't fork a shell.
>

Oh () hiding in there. N/m

Warner

>
> Warner
>
>
>> > On Aug 3, 2026, at 11:47 PM, Arnold Robbins via TUHS <tuhs at tuhs.org>
>> wrote:
>> >
>> > Warner Losh via TUHS <tuhs at tuhs.org> wrote:
>> >
>> >> I've not examined the source to Thompson shell closely to know if it
>> >> secretly does this (and that's why Steve Bourne implemented it), or if
>> >> that's something Bourne invented.
>> >
>> > Braces are also allowed where "do" and "done" are.
>> >
>> > I have always suspected, but never bothered to verify, that this is
>> > the case so that shell scripts could look more like C if one wanted
>> > them to. For example, in Bash:
>> >
>> > $ for ((i = 1; i <= 3; i++))
>> > > {
>> > >     echo $i
>> > > }
>> > 1
>> > 2
>> > 3
>> >
>> > Arnold
>>
>>