Which command is used to assign a swap signature to a device?

• A. mkswap
• B. swapon
• C. mkswap -a
• D. cat /proc/swaps

Answer: (A)

Assigning a swap signature to a device is the step that prepares the device so the kernel can recognize it as swap. The command that creates that signature is mkswap; it writes the swap header and metadata to the partition or file, turning it into a swap area that can later be enabled with swapon. Swapon activates an already prepared swap space, so it doesn’t create or modify the signature. The option mkswap -a would attempt to prepare all swap entries listed in /etc/fstab, which isn’t the standard, single-device preparation. Viewing /proc/swaps shows currently active swap spaces, not the act of creating the signature.