Transparent recovery of self-sustained code-upgrade

摘要

A defective self-sustained code-upgrade code is recovered. A relevant unset variable is set to avoid an un-initialized command failure. A relevant set variable is unset to render a second invocation of the set variable to appear as a first invocation A fix-named file is retrieved containing a plurality of code entries organized in a stanza style. The fixed-named file is executed. The plurality of stanza-organized entries are sourced by the defective code-upgrade code to change a variable which has been previously set, thereby overriding an existing process.