How to write a script bash to enter multi-line input in jupyter-notebook?

For your particular case, you can simply use semicolon at the end to run it i.e.

!(python --version; \ which python; \ pip --version; \ conda --version; \ which conda) >> config-environment.txt

For general case, you can use %%bash cell magic command to run the cell in bash i.e.

%%bash script magic
Run cells with bash in a subprocess.

%%bash(python --version which python  pip --version  conda --version  which conda) >> config-environment.txt

You can also have a look at subprocess python module.

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