[em-bee]

you execute them like any other script. the script is not interpreted by your interactive shell but it specifies which shell/interpreter will be used to run it. that interpreter is then started for this script. your interactive shell does not limit what kind of scripts you can run. there was never a requirement that bash scripts need to be started from a bash shell. otherwise you could not even run python or other scripts from your shell.

[throwaway290]

Ah. I meant cases where lazy third-party scripts just assume my current shell is POSIX and don't explicitly make themselves run in bash.

[Macha]

Run "bash thirdparty.sh" instead of "./thirdparty.sh" to force bash.

[em-bee]

if there is a bash script that does not start with #!/bin/bash where the instructions say to run it in bash, then it can be run as bash scriptfile; or cat scriptfile | bash;. both these forms work from any commandline shell

[throwaway290]

Yes. But I need to inspect the script to know to do it (or hope that if it didn't fail then it truly didn't fail). I am not saying it's an insurmountable challenge, just that there is some friction when using fish.

[em-bee]

not really, unless there is a clear indication that it is a fish script, i's just asume it is bash and run it with that.

it's only work if the commands need to be run within fish itself and not a subshell. there are tools for that but i agree that sometimes i can't be bothered and then i'll just work in bash to do that job.

[throwaway290]

For example if I follow some README I may not even know whether it's a script or binary, so I guess I would need to know at least that before I run something with bash (or get "cannot execute binary":)