[bluetomcat]

The way the shell works is an essential part of Unix design, and the fork/exec pair suits it very well. In the forked child process before the exec, the shell can execute arbitrary code that inherits all file descriptors and manipulates/redirects them in a certain way.

[tsimionescu]

I didn't say it's useless, I said it's a niche utility. There are, what, 10 even slightly commonly used shells?

Compared to the thousands of other programs that spawn processes, I think shells count as a niche use.

If fork() and exec() had been kept as the niche utilities they are in addition to a more commonly used spawn() syscall, fork() and exec() could have remained simple and small, and not needed all the CoW magic and many other complex features at all.

[hawski]

I wonder now if one could emulate fork-shenanigans-exec by:

- clone CLONE_FILES with AF_UNIX socketpair

- send file descriptors through the socket

- do whatever was in shenanigans (you have the socket for communication/RPC/whatever)

- exec

or maybe even easier:

- clone CLONE_FILES with pipe or two

- do whatever was in shenanigans (you have the pipe for communication/RPC/whatever)

- exec