Naitsirhc's code

import os, osproc, strutils, parseopt, strtabs

const printVarsScript = "/tmp/printVars.sh "

proc createScript(): void =
  if existsFile(printVarsScript.strip) != true:
    echo("Creating script")
    writeFile(printVarsScript.strip,
      "#!/bin/sh \n" &
      "tmpa=/tmp/a \n" &
      "tmpb=/tmp/b \n" &
      "set -a \n" &
      "env > $tmpa \n" &
      ". $1 \n" &
      "env > $tmpb \n" &
      "diff $tmp{a,b} | sed -ne 's/^> //p' \n" &
      "rm $tmp{a,b} \n")
  return

proc confVar*(confFile: string): PStringTable =
  createScript()
  var
    command = "sh " & printVarsScript & confFile
    commandResult = execCmdEx(command)
    rawVars = commandResult.output.strip
  result = newStringTable(modeCaseSensitive)

  for line in splitLines(rawVars) :
    var
      lineSplit = split(line, '=')
    result[lineSplit[0]] = lineSplit[1]

  return