Execute bash inside subshells

Question

Say I have a command that puts me into a subshell (e.g. nix-shell). If I have a bash script that goes

enter-subshell
echo hi

the echo hi will wait to be executed until I exit the subshell. Is there any way to write a script that behaves the same as manually typing out both lines in order? In other words, subsequent commands get executed in the newly invoked shell?

Edit: it seems what I'm looking to do doesn't have a general solution.

Answer 1

You'll have to create a script and invoke that shell calling your script as a parameter. For example:

$ echo "echo hi" > my_echo.subshell
$ echo "enter-subshell -c my_echo.subshell" > my_script.bash
$ ./my_script.bash

The way to pass parameters to the subshell (in my example "-c") will depend on your subshell, each shell might use a different parameter.

As an alternative, if you don't want to create a second script, you can also redirect instructions to the shell. It will also vary and depend on the shell you want to call. For example:

enter-subshell -e <<EOF
echo hi
EOF

For this method, you can read more on "Here Documents". Again, you will find the proper way of executing the specific subshell (in my example "-e").