How do I monitor swap usage?

You can monitor swap usage in Linux using several command-line tools. Here are a few methods:

Using the free command:
```
free -h
```
This command displays memory and swap usage in a human-readable format.
Using the swapon command:
```
sudo swapon --show
```
This command shows the swap space currently in use, including the size and usage of each swap file.
Using the top command:

Run the top command:
```
top
```
In the output, you will see a summary of memory and swap usage at the top of the screen.
Using the vmstat command:
```
vmstat 1
```
This command provides a continuous report of system performance, including swap usage, updated every second.
Using the htop command (if installed):

Simply run:
```
htop
```
This interactive process viewer shows memory and swap usage in a graphical format.

You can choose any of these methods based on your preference for monitoring swap usage.