how to use nft command line to set an element value to empty

To set an element value to empty using the NFT command line, you can use the set command with the appropriate options. Here's how you can do it:

Open the command line or terminal on your system.
Use the nft command to access the NFT command line interface.
Identify the table and chain that contain the element you want to modify. For example, if you want to modify an element in the filter table and input chain, you can use the following command:
```
nft list table filter
```
Find the specific element you want to modify and note its position or unique identifier.
Use the set command to modify the element. The syntax for the set command is as follows:
```
nft set element <table> <chain> <position or identifier> <attribute> <new value>
```
Replace the <table>, <chain>, <position or identifier>, <attribute>, and <new value> placeholders with the actual values relevant to your setup. For example, to set an element value to empty in the filter table, input chain, at position 3, and for the src attribute, you can use the following command:
```
nft set element filter input 3 src ''
```
Note: Replace '' with "" if your system requires double quotes instead of single quotes.
Execute the command to set the element value to empty.

Make sure to adjust the command according to your specific use case and element attributes