On 6/23/21 6:24 AM, Chet Ramey wrote:
On 6/22/21 9:54 PM, Martin Jambon wrote:
In the posix definition, a subshell
- is not necessarily implemented as a separate process
- belongs to a unique shell
- is not a shell
Why is it not "a shell?"
Because '$$' doesn't match its process ID.
What is the magic quality that imparts shellness?
'$$' matching the process ID.
Posix: '$' shall expand to the same value as that of the current shell.
(https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_05_02)
Bash: ($$) Expands to the process ID of the shell.
(https://www.gnu.org/software/bash/manual/bash.html#Special-Parameters)
I'm not sure why I have to fight over this. It's clearly my
misunderstanding. That's why I suggest clarifications in the
documentation, if you're interested in creating a better experience for
users like me.
