Setting up a RAM drive on Raspberry Pi
It is strongly believed that excessive writing to the Raspberry Pi's SD card will finally cause it to fail. But the only way to exchange data between Lua and shell scripts is through temporarily files. To avoid SD card wearing these files could be written to a virtual drive in RAM. This guide shows how to set up a 1 MB RAM drive on your Raspberry Pi.
For more elaborate instructions, see Moving Log and Temporary Files To a RAM Drive
Goal is to have a 1MB directory in RAM for temporarily storage.
First create the tmp dir:
sudo mkdir /var/tmp
then edit the fstab file by
sudo nano /etc/fstab
and add the line
tmpfs /var/tmp tmpfs nodev,nosuid,size=1M 0 0
save and close the file. Now issue
sudo mount -a
To check if your operation succeeded issue
which should report (among the other disks) a tmpfs with 1024 1K blocks (=1MB) as /var/tmp
pi@raspberrypi ~ $ df Filesystem 1K-blocks Used Available Use% Mounted on rootfs 3807952 1814024 1820896 50% / /dev/root 3807952 1814024 1820896 50% / devtmpfs 183596 0 183596 0% /dev tmpfs 38372 268 38104 1% /run tmpfs 5120 0 5120 0% /run/lock tmpfs 76740 0 76740 0% /run/shm /dev/mmcblk0p1 57288 18544 38744 33% /boot tmpfs 1024 4 1020 1% /var/tmp
This should give you a small space for your garbage. Instead of writing your tmp files to /tmp, now write them to /var/tmp. And remember that, as is generally the case with RAM drives, data on the drive is lost after a reboot.