{bash} is used for everything that concerns bash commands and LaTeX like using the package {bashful}.
bash is used for everything that concerns bash commands and LaTeX like using the package bashful. If your question is about displaying bash code in a LaTeX document, use the code tag, and consider the listings or minted packages. If your question includes questions about scripts in other languages, look into the scripts tag.
Syntax Highlighting
If your question or answer includes bash code, you can syntax highlight it by doing the following:
<!-- language: lang-bash -->
code goes here
You can also use lang-csh for csh code. More information here.
Here's an example of what it looks like:
#!/bin/bash
echo "Hello, world!"