How Do I Decrease the Size of a Preexisting Swap File Without Removing it?

Question

After seeing this post: How do I increase swapfile in Ubuntu 18.04?, I was wondering, how do I decrease the size of the swap file without removing it?

Answer 1

how do I decrease the size of the swap file without removing it?

This question is rather irrelevant. Swap space must be taken out of use before changing it. The command sudo fallocate -l 4G /swapfile (with an adjusted size) will overwrite your existing swapfile if you do not delete it first.