ubuntu linux: create a ramdisk

$ sudo -s
# free -m    # (optional) to check how much memory left on system
# mkdir /tmp/ramdisk; chmod 777 /tmp/ramdisk
# mount -t tmpfs -o size=256M tmpfs /tmp/ramdisk/
# exit

ubuntu: file archiver 開rar 檔內中文檔名有亂碼

sudo apt-get remove rar unrar
sudo apt-get install p7zip-full p7zip-rar