保留文件系统下剩余指定数目的文件的shell脚本

#!/bin/bash 
#------------------------------- 
#Description: Back up your files
#site: www.jiaochengji.com
#------------------------------- 
 
#shell 变量
path_source=/mnt/fifth/shell 
path_backup=/mnt/fifth/backup/shellbackup 
path_delete=/mnt/fifth/tmp/rubbish/ 
limit_num=15 
 
fileBackup() 
{ 
set -x 
#备份文件
#cp -r $1 $2/shell-`date +%Y-%m-%d-%H-%M-%S` 
count=`ls $1 | wc -w` 
 
if [ "$count" -gt "$3" ];then 
    echo "-----------------limit is : $3 ----------------------" 
    echo "-----------------The number of files is : $count -------" 
    num=`expr $count - $3` 
    echo "-----------------The excess number of files is : $num ---------" 
#移动文件 
    ls $1 -1rt | head -n $num|xargs -n1 -i mv $1/{} $2 
    set +x 
    ls -1rt $2 
    echo "-----------------Moving end!-----------------" 
else 
    ls -1rt $2 
    echo "-----------------The file is too little!-------------------" 
fi 
}
 
#备份shell脚本 
fileBackup $path_backup $path_delete $limit_num