Support defaulting launch & proc-run to use $SHELL with option for --no-shell otherwise

[chipsenkbeil]

At least for launch (proc-run may not be necessary), being able to take advantage of the path assigned to a user would be handy.

Testing with ssh <host> echo '$SHELL' resulted in the right shell being printed, so that environment variable is available. It looks like the majority of shells support <shell> -l for login and <shell> -c <command> to run a command as non-login. Doesn't look like you can run a login shell and execute a command, but I don't think a login shell is necessary to get the path configured for the specific user as non-login will still source files like ~/.bashrc and others.

Anyway, idea here is to default to attempting to run distant over ssh using $SHELL -c distant ... to have appropriate environment variables established. If --no-shell is provided, then we wouldn't wrap in a $SHELL call.

Doing this for proc-run may not make sense as any environment given to the distant binary is passed on to its children; so, just providing launch with $SHELL should pass on the results to the children as well.

[chipsenkbeil]

It looks like we may actually need the login shell option. Bash, ksh, fish, and zsh support providing a login shell and command option together <shell> -l -c env. The shells csh and tcsh do not, but the recommendation is to do something like echo ls | tcsh -l.

So idea would be to do something like echo 'distant ...' | $SHELL -l

[chipsenkbeil]

Resolved by 160631b

[wez]

If you integrate libssh or libssh2, you can have the sshd give you a login shell by requesting a shell explicitly, and then you can send your commands on stdin, which is sort of in alignment with your comment above, but you shouldn't need to play around with $SHELL or figuring out how to spawn a login shell.

Also note that if you were in control of the spawning directly (which I know you're not in this case), spawning a login shell can be done this way in rust:

            let shell = Self::get_shell()?;
            let mut cmd = std::process::Command::new(&shell);
            // Run the shell as a login shell by prefixing the shell's
            // basename with `-` and setting that as argv0
            let basename = shell.rsplit('/').next().unwrap_or(&shell);
            cmd.arg0(&format!("-{}", basename));

https://github.com/wez/wezterm/blob/main/pty/src/cmdbuilder.rs#L190-L197

[wez]

FWIW, the $SHELL -l thing doesn't work with fish; I know because that's the technique I used to use in wezterm!

[chipsenkbeil]

Good call out about fish :) If I get to the point of incorporating an ssh client and have the control you mentioned, I'd definitely switch to that! For now, fish users would include `--no-shell`

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On Mon, Aug 16, 2021, 6:02 PM Wez Furlong ***@***.***> wrote: FWIW, the $SHELL -l thing doesn't work with fish; I know because that's the technique I used to use in wezterm! — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#28 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAS55CSMOLVNJJQCKI2ABLLT5GKHXANCNFSM5CIIIEZA> .

[github-actions]

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