Comment by uecker
1 day ago
A lot of features of UNIX shells are build around pipe and dup and the fork + exec model. One can certainly implement in differently, but it is - like UNIX in general - very nice and elegant.
1 day ago
A lot of features of UNIX shells are build around pipe and dup and the fork + exec model. One can certainly implement in differently, but it is - like UNIX in general - very nice and elegant.
It's an elegant hack, but it's still a hack. Not what we should be doing in 2026.
I would prefer to continue to use elegant interfaces even beyond 2026.
I would prefer to use elegant interfaces that aren't massive hacks.
3 replies →
Help me out here, please. Off the top of my head, the exec command is dependent on exec, except that a spawn + wait implementation would be a mostly okay substitute.
Pipes and redirections don’t need fork + exec. Neither do subshells.
If you use pipe() you get two ends in the same process, then you fork and child and parent can communicate. This is how a unix shell setups up pipes and it is rather elegant.
Doing the same thing on Windows, I create the pipe and get two ends in the same process. Then I'd call CreateProcess and indicate I want the pipe's handle (fd) inherited to the child, and I'd use a prearranged way to tell the child what the fd value is it should use.
Possibly the most common way to tell the child the value is by setting it as a CLI arg in CreateProcess.
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