Shell中显示时间差

begintime=`date +%s`                                                                                                                
sleep 2s
endtime=`date +%s`
duration=$(($endtime-$begintime))

current=`date   +%Y/%m/%d-%H:%M:%S` 

echo   $current

echo $begintime
echo $endtime

echo $duration in seconds
echo $(($duration/3600)) in hours

echo $(($duration/86400)) in days

创建以日期命名的目录

mkdir `date +%Y%m%d`.dir