#!/bin/bash

function return_sids(){
  cat oratab | grep -Ev '^#|^$' | while read LINE
    do
      SID=$(echo $LINE | awk -F":" '{print $1}' | tr '[:upper:]' '[:lower:]')
      DIR_SID=$(echo $LINE | awk -F":" '{print $2}' | awk -F"/" '{print $3}')
      if [[ "$SID" = "$DIR_SID" ]]
        then
          echo $SID
      fi
    done
}

return_sids