support Dash as /bin/sh

[JtMotoX]

I am using Dash for /bin/sh and the Asahi installer fails with "Your version of cURL is too old". This is because the curl check uses &>/dev/null which Dash does not support. Updating to use the more compatible >/dev/null 2>&1 instead.

> curl https://alx.sh | sh
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  2289  100  2289    0     0   4364      0 --:--:-- --:--:-- --:--:--  4368
Your version of cURL is too old. This usually means your macOS is very out
of date. Installing Asahi Linux requires at least macOS version 13.5.

> sw_vers
ProductName:		macOS
ProductVersion:		15.1.1
BuildVersion:		24B91

> what /bin/sh
/bin/sh:
	PROGRAM:sh  PROJECT:dash-16
	PROGRAM:sh  PROJECT:dash-16

> /bin/sh -c 'if ! date &>&1; then echo "something wrong"; else echo "something right"; fi'
something wrong
Fri Nov 29 14:21:27 PST 2024

> /bin/sh -c 'if ! date >/dev/null 2>&1; then echo "something wrong"; else echo "something right"; fi'
something right

[Conan-Kudo]

How are you using Dash as /bin/sh on macOS? It should only support zsh or bash...

[JtMotoX]

Yes, I am and have been for years. The development I do requires POSIX-compliance. This asahi installer is the only thing I have ever encountered compatibility issues with using dash.

[Conan-Kudo]

I've merged this pull request as the change is trivial, but please be aware that we make no guarantees or provide any expectations that our scripts will remain POSIX sh compatible. Using a shell other than bash or zsh to execute our scripts on macOS remains fully unsupported.

[JtMotoX]

Understood. And thank you for merging. 👍 After I made these changes locally, I was able to fully install Asahi on my dash mac.