удалить все файлы кроме последних 70 - скрипт, как?

#!/bin/bash

cd /PD_nfs/MEOS

echo $(date)

##define variables
address="email@email.com"


#ls -ltr | tail -n1 | awk '{print $8}'
#find /data -type f -mmin 20 -exec stat -c '%Y %n %y' {} + | sort -k1nr | head -1

while true; do
    COUNT=$(find . -mmin -10 -type f | wc -l)
    echo $(pwd);
    echo $(date);
    echo "last file date: " $(ls -ltr | tail -n1 | awk '{print $8}');
    find . -mmin -10 -type f | wc -l ;
timestamp=$(date +%Y%m%d_%H%M%S)
path="/Second"
filename=log_check_flow_$timestamp.txt
log=/Second/$filename
START_TIME=$(date +%s)
END_TIME=$(date +%s)
ELAPSED_TIME=$(expr $END_TIME - $START_TIME)

find . -mmin -10 -type f | wc -l >> $log;
find . -mmin -10 -type f | head -n15 |tee -a $log

echo "find output for 20 minutes :  " >> $log
find . -type f -mmin 20 -exec stat -c '%Y %n %y' {} + | sort -k1nr | head -1 >> $log

echo " " >> $log
echo " ls -ltr output: " >> $log
ls -ltr | tail -n1 | awk '{print $8}' >> $log

#remove old logfiles:
pwd
date >>$path/log_rm.txt;
ls -t -r $path/log_check*.txt |head -n -70 
ls -t -r $path/log_check*.txt |head -n -70 |xargs rm  -rfv >>$path/log_rm.txt;
#ls -t -r $path/log_check*.txt |tail -n +18 |xargs rm  -rfv >$path/log_rm.txt;

echo "remove_old_logfiles pass"

#echo "Backup :: Script End -- $(date +%Y%m%d_%H%M)" >> $log
echo "Checking :: Script End -- $(date +%Y%m%d_%H%M)" >> $log
echo "Elapsed Time ::  $(date -d 00:00:$ELAPSED_TIME +%Hh:%Mm:%Ss) "  >> $log

# check for rm logfile size:

echo "rm_log size now is: "    
du $path/log_rm.txt | cut -f1
    
    if [[ $(du $path/log_rm.txt | cut -f1) -gt 100 ]]; 
    then echo 're-arm log_rm';
    cp $path/log_rm.txt $path/log_rm.old; 
    :>$path/log_rm.txt  
    fi


    if [ $COUNT = 0 ]; then
        #ACHTUNG!!!
    last=$(ls -ltr | tail -n1 | awk '{print $8}');
    body=" Admin, we have problems on SER2! last incoming files was:  $last" ;
    echo -e $body | mail -S smtp=214.50.70.11 -S from=outgoing@email.com -s "Warning on SER2" -c email2@email.com  $address;

    fi
    sleep 360
done;