Revert "use source instead of bash to support export command"

This partially reverts commit af6d1b2e47f922dcc2ef83d0ac70d31ef0d245f2.
Revert "export scripts bin path immediately"

This reverts commit ef2cd33eb964d5327cbee785614c076e1de0526d.
Revert "add scripts to path"

This reverts commit 8f54b6a603b3255f3d0bc8d34dee1bb25d4f864e.