-- Test environment variables
print("Current shell: " .. $SHELL)

-- Test environment variable assignment
$HELLO = "my variable"
print("HELLO = " .. $HELLO)

-- Test $VAR inside strings (should NOT be substituted)
print("This should print literally: $SHELL and $HOME")

-- Test $VAR outside strings (should be substituted)
print("Home directory: " .. $HOME)

-- Test shell commands
current_dir = `pwd`
print("Current directory: " .. current_dir)

-- Test interactive command
!echo "Running interactive command"