swapoff
swapoff功能说明：关闭系统交换区(swap area)。
语 法：swapoff [设备]
补充说明：swapoff实际上为swapon的符号连接，可用来关闭系统的交换区。
swapoff
swapoff [options] [devicelist]
System administration command. Stop making devices and files specified in devicelist available for swapping and paging.
Option
Consult /etc/fstab for devices marked sw. Use those in place of the device argument.
Print help message and then exit.
Display version number and then exit.