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. |
If you encounter the below error while running the swapon command:
swapon: command not found
you may try installing the below package as per your choice of distribution:
| OS Distribution | Command |
|---|---|
| OS X | brew install util-linux |
| Debian | apt-get install mount |
| Ubuntu | apt-get install mount |
| Alpine | apk add util-linux |
| Arch Linux | pacman -S util-linux |
| Kali Linux | apt-get install mount |
| CentOS | yum install util-linux |
| Fedora | dnf install util-linux |
| Raspbian | apt-get install loop-aes-utils |
swapon Command Examples
1. Consult /etc/fstab for devices marked sw. Use those in place of the devices argument.
# swapon -a
2. Used with -a. Don’t complain about missing devices.
# swapon -ae
3. Print help message, then exit.
# swapon -h
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.
# swapon -V