Great question, Benjamin! The behavior you're observing is completely normal in Bash, and here's why:

Why the alias doesn't work inside the if block

• Aliases are not expanded in non-interactive shells by default. When you run a script or a block of code (like inside an if statement), Bash does not expand aliases unless you explicitly enable it with shopt -s expand_aliases.

• Aliases are shell-specific. Even if you enable alias expansion, the alias my_test is only available in the current shell instance where it was defined. If the if block is run in a subshell (which is not the case here, but it's a common point of confusion), the alias would not persist outside of it.

How to fix it

If you want to use an alias inside a script or a block, you need to enable alias expansion at the start of your script or block:

shopt -s expand_aliases
if true
then
    alias my_test='echo test'
    my_test
fi

Or, more simply, use a function instead of an alias for scripts:

if true
then
    my_test() { echo test; }
    my_test
fi

Functions are expanded in non-interactive shells and are generally more reliable for scripting.

Summary Table

Would you like to explore more about Bash scripting or aliases?