mcc, 28 days ago

I found this exact question answered in a FAQ titled "fish for bash users": https://fishshell.com/docs/current/fish_for_bash_users.html#subshells

But my interpretation of its FAQ answer is "if this is what you want, have you considered simply wanting something different?"

fabiosantoscode, 28 days ago

@mcc ugh, I thought I heard fish was good?

juandesant, 28 days ago

@mcc is not exactly the same, but could you not do $(fish -c "cd .. ; ls ") inside of fish?

juandesant, 27 days ago

@mcc just tested in iSH after installing fish with apk add fish:

localhost:~# fish -c "ls"  
juandesant.rss  
localhost:~# fish -c "echo $(fish -c ls)"  
juandesant.rss  
localhost:~# fish -c "$(fish -c ls)"  
fish: Unknown command: juandesant.rss  
fish:   
juandesant.rss  

juandesant.rss is the only file in that directory.

virtulis, 28 days ago

@mcc Well (pushd ..; ls; popd) seems to work, but it's three commands technically.

Edit: it's most certainly not a rubber room either. Is it in bash?

mcc, 28 days ago

@virtulis for me this gives the same error about command substitution. but even if it did not, it's not quite the same because it will have different aborting behavior. I guess… if the middle one fails, does popd execute unconditionally?

mcc, 28 days ago

@virtulis I tried {ls} and it gave me something about "use begin; end;" . This isn't my shell/computer so I'm a little confused…

unlambda, 28 days ago

@mcc well, they do also say "if you really need it, just invoke fish -c 'your code here'"

So they get that some people really do need it, but they don't provide any feature for it, just the usual "you can always invoke fish as a separate process"

mcc, 28 days ago

@unlambda @henryk Yeah, I'm not super impressed with this because now I gotta fiddle with a whole level of escaping?

jferg, 28 days ago

@mcc Per that doc, is

fish -c 'cd .. && ls'; ls

not what you're looking for? It's definitely more unwieldy, and I'm not sure about piping stuff between the first command and second.

mcc, 28 days ago

@jferg Thanks, I see it but the problem is now I have to think about escaping. It's awkward enough I'd wind up doing it another way…

shironeko, 28 days ago

@mcc is this for a script?

mcc, 28 days ago

@shironeko just at the command line

shironeko, 28 days ago

@mcc in that case I would just type "fish" do what I need and type "exit"

mcc, 28 days ago

@shironeko so the actual line is something like

(cd .. && ../build.sh) && dotnet run

and the goal is to be able to invoke this one line that does various things in different places, but get sensible rollback behavior (IE not find ourselves in another directory) if something fails partway through.

I thnk I can still emulate it with something like

pushd .. && build.sh && dotnet run | popd

but it'll be awkward

rst, 28 days ago

@mcc Parentheses for subshells isn't just bash, it's at least as old as the original Unix v7 Bourne shell, and is required of /bin/sh by Posix. (It's reasonable to have a shell that deliberately deviates from the Posix spec, but, well... fish appears to be one of those.)