保留指定次数的备份

#! /bin/sh
# 备份日志路径
backup_log_path=/test_bak/logs/
# 获取当天的日期
data=$(date + "%Y%m%d")
# 备份目录
dir=/test_bak/
# 备份保留次数
count_keep=3

cd $dir

ls $dir | grep test > $dir/a.txt
num=`wc -l $dir/a.txt | awk '{print $1}'`
if [[ ${num} -eq $(($conut_keep+2)) ]]
then
    sed -n -e '2p' $dir/a.txt > $dir/del.txt
    cat $dir/del.txt | while read var;do
    echo delete the older version >> $backup_log_path/copy$date.log
    rm -rf $dir/$var
    rm -rf $dir/del.txt
    done
fi
rm -rf $dir/a.txt