小编Ins*_*are的帖子

BASH 手册页local说

local [option] [name[=value] ... | - ]
    […] If name is ‘-’, the set of shell options is made local to the 
    function in which local is invoked: shell options changed using the
    set builtin inside the function are restored to their original
    values when the function returns.

因此，根据这些信息，使用local -，我应该能够set -x在函数内部使用来启用跟踪输出。当函数结束时，跟踪输出将被禁用。

#!/bin/bash
foo() {
  local -
  set -x
  ... # this code is shown in trace output
}

# trace output is …