Fix environmental variable expansion

[WeidiDeng]

Description
Fix 1211.

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[o1egl]

Please remove search related commits from this pr.

[WeidiDeng]

I found out that there is a global setting called Execute on shell that is supposed to do the envars expansion. Guess that's overlooked.

Also user executed command on the built-shell is affected by that setting too. I think documentation needs to be made more specific.