Question

I have the following bash script (named “env.bash”) to be consumed by the source command:

#!/bin/bash
FOO=/some/path

Then I have the following bash script (named “compile.bash”):

#!/bin/bash
if [ -z "$FOO" ]; then
    echo "Need to set FOO, did you forget to source env.bash?"
    exit 1
fi 
./compile-something

However, if I do:

source env.bash
./compile.bash

I get “Need to set FOO”, why? If I echo $FOO I can see its value just fine.

Answer 1

export FOO=/some/path

This should work. The reason is that a shell script will run in a sub-shell, which has its own copy of the environment; the variables of the super-shell are not normally visible. When you perform an export, you will make the copies of the exported variables available to sub-shells.

EDIT: Removed inaccuracies; also, thanks @DonCallisto for a good point.