The swapon command is used to activate a swap partition in a specified device. The swapoff command is used to deactivate the swap space on a device.

Some of the frequently used swapon and swapoff command options are given in the following table.

Option Used To
swapon -e Skip non-existent devices.
swapon -a Activate all of swap space.
swapoff -a Deactivate all of swap space.

swapon Command Examples

1. Consult /etc/fstab for devices marked sw. Use those in place of the devices argument.

2. Used with -a. Don’t complain about missing devices.

3. Print help message, then exit.

4. Specify a priority for the swap area. Higher priority areas will be used up before lower priority areas are used.

# swapon -p 5 /var/tmp/swapfile

5. Print swap usage summaries, then exit.

# swapon -s
Filename				Type		Size	Used	Priority
/dev/dm-1               partition	268435452	0	-1
/swapfile               file	      102396	0	-2

6. Print version information, then exit.

swapoff Command Examples

1. Consult /etc/fstab for devices marked sw. Use those in place of the device argument.

2. Print help message and then exit.

3. Display version number and then exit.