UNIX for Advanced & Expert Users

#!/bin/ksh
filetime()
{
    perl  -e '
         $mtime = (stat $ARGV[0])[9];
          print $mtime;
         '  $1
}
now=$(date +%s)
now=$(( $now - 14400 ))
find /path/to/file -type f | \
while read filename 
do
     ftime=$(filetime $filename)
     if [[ $ftime -ge $now ]] ; then
        continue
     fi
     rm -f $file
done

touch -t YYYYMMDDhhmmss /tmp/touchfile
find ./ -older /tmp/touchfile -exec rm -f {}\;

touch -t [4hours ago] touchfile
find /path/to/files ! -newer touchfile  -exec rm -f {} \;