```bash
#!/bin/bash
set -e
FreeSpace=`free -h|awk '/^Mem/ {print $4}'`
if [ $FreeSpace -lt 600M ];then
echo 1 > /proc/sys/vm/drop_caches
echo 2 > /proc/sys/vm/drop_caches
echo 3 > /proc/sys/vm/drop_caches
fi
```

内存释放脚本