Android emacs: How to deal with Shebang in doom scripts?

[johanwiden]

I confirm that...

• I have searched the issue tracker, documentation, FAQ, Discourse, and Google, in case this issue has already been reported/resolved.
• I have read "How to Debug Issues", and will use it to provide as much information about this issue as possible.
• The issue can be reproduced on the latest available commit of Doom.
• The issue can be reproduced on a stable release of Emacs, such as 27, 28, or 29. (Unstable versions end in .50, .60, or .9x)

Expected behavior

It has recently become possible to use doomemacs in Android emacs: https://www.reddit.com/r/emacs/comments/1aif4wy/use_doomemacs_on_android/
A stumbling block is that Android does not recognize /usr/bin/env in script Shebang.
There is an env command in Termux, but the path to env from Android emacs does not start with "/usr/bin".
So I change the Shebang to "#!/system/bin/sh", which of course is not portable. But if I modify anything in
~/.config/emacs then I can not run "doom upgrade".
So can we perhaps in doom/bin have a parallel set of scripts, for Android emacs, with just the Shebang changed to
"#!/system/bin/sh". Or is there a better mechanism?
I am of course willing to help, and can make a pull request, or whatever, but perhaps someone has a better idea?

Current behavior

The doom script out of the box, fails to run because /usr/bin/env is not found.

Steps to reproduce

Start Android emacs. Try to execute the unmodified doom script.

System Information

https://pastebin.com/qynKKPfL

[hlissner]

Presumably, you have root access to your android device, so couldn't /usr/bin/env be symlinked to wherever Android/Termux's env is?

Shebang lines are dreadfully inflexible, and I'd rather avoid having to maintain multiple parallel scripts with nightmare shebang lines for various nonstandard systems, especially those I don't dogfood/cannot personally test.

[johanwiden]

No, I do not have root access to my android device. Android emacs is a regular android app. I see that there is a script doom.cmd in the bin directory. Does that work well? Then one could presumably create a similar shell script, for android. Den ons 7 feb. 2024 kl 22:41 skrev Henrik Lissner ***@***.***

…

: Presumably, you have root access to your android device, so couldn't /usr/bin/env be symlinked to wherever Android's env is? Shebang lines are dreadfully inflexible, and I'd rather avoid having to maintain multiple parallel scripts with nightmare shebang lines <https://github.com/doomemacs/doomemacs/blob/master/bin/doom#L1-L14> for various nonstandard systems, especially those I don't dogfood/cannot personally test. — Reply to this email directly, view it on GitHub <#7655 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAOF7OJCM5PN2JUL72OZ7WLYSPYKBAVCNFSM6AAAAABC54JKSSVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSMZSHE4DKNRWGU> . You are receiving this because you authored the thread.Message ID: ***@***.***>

-- Johan Widén, tel: +46705367346 Risvägen 5 A, 192 73 Sollentuna, SWEDEN

[hlissner]

Does that work well?

It does not work at all (case in point). I've been meaning to remove it, in fact. It might've worked in the past, but the API has changed, and without a consistent Windows test system in my life, I haven't gotten around to updating it. That said, Windows users have a far better alternative (e.g. installing Emacs via WSL or git-bash), so it's not a big loss.

---

How about creating a doom shim somewhere higher in your $PATH? E.g. Assuming ~/.local/bin has higher precedence in your $PATH than ~/.emacs.d/bin:

(For example, in ~/.local/bin/doom)

#!/bin/sh
# ^ update shebang path as needed
sh "$HOME/.emacs.d/bin/doom" "$@"

(Don't forget to make it executable, w/ chmod +x ~/.local/bin/doom)

This way, the script lives outside of the Doom tree (and so not impacting doom upgrade), and invokes the Doom script explicitly with the shell of your choice.

You could also launch Doom this way directly, in your shell. E.g.

sh $HOME/.emacs.d/bin/doom sync

I may not be willing to make copies of bin/doom (just for different shebangs), but I could factor what works for you into an installer I'm working on (to replace doom install with something more portable, which can take care of issues like these for more systems).

[johanwiden]

Using a shim did not work as expected: Android seems to cache (and verify?) scripts, and then use the cached version. I instead did the following, which I believe is a good enough solution: - doom upgrade --force - Update Shebang in doom script (see script for this below), update PATH in early-init.el (as described in the reddit thread). - doom sync -u Note: The update of PATH in early-init.el, described in the reddit thread could be improved: It ought to check if PATH already has a termuxpath component. And here is a script that conditionally modifies the Shebang in a set of files: ```sh #!/system/bin/sh for i in $@; do grep -q '^#!/usr/bin/env sh' $i && sed -i '1 s;/usr/bin/env sh;/system/bin/sh;' $i done ```