邮件删除脚本改进

哪位大侠帮忙看看这段脚本如果再进行优化的话该如何改进能提高执行效率呢？多谢多谢，不胜感激。

#!/bin/sh
#

if [ ! -d /home/mail/queue/mess ]
then
echo "exit"
exit
fi

cd /home/mail/queue

ls mess|while read msgdir
do
echo $msgdir
cd /home/mail/queue/mess/$msgdir
ls|while read ofl
do
fl=`head -20 $ofl | grep MAILER-DEAMON |grep -i From` \\并联分析，查找“来自发信人”“MAILER-DEAMON”的邮件
if [ x"$fl" != x ]
then
echo $ofl
if [ -f /home/mail/queue/info/$msgdir/$ofl ]
then
echo ----$ofl
rm -f $ofl
rm -f /home/mail/queue/info/$msgdir/$ofl
rm -f /home/mail/queue/remote/$msgdir/$ofl
rm -f /home/mail/queue/emsg/$msgdir/$ofl
rm -f /home/mail/queue/intd/$ofl
rm -f /home/mail/queue/pid/$ofl
rm -f /home/mail/queue/todo/$ofl
rm -f /home/mail/queue/bounce/$ofl
else
if [ -f /home/mail/queue/todo/$ofl ]
then
echo ----$ofl
rm -f $ofl
rm -f /home/mail/queue/info/$msgdir/$ofl
rm -f /home/mail/queue/remote/$msgdir/$ofl
rm -f /home/mail/queue/emsg/$msgdir/$ofl
rm -f /home/mail/queue/intd/$ofl
rm -f /home/mail/queue/pid/$ofl
rm -f /home/mail/queue/todo/$ofl
rm -f /home/mail/queue/bounce/$ofl
else
echo "reserve"
fi
fi
fi
done
done
exit