# .chain command (Output processor)

The .chain command passes control to
a specified item-ID in the same (current) file or in a different (file
reference) file.

Note: Control does not return to the source item after executing
the .chain command item.

## Syntax

```
.chain {dict} {file.reference} item-ID
```

## Parameter(s)

| dict | Specifies the dictionary where the file change resides. This parameter is optional. If not specified, the data section of the file is assumed. |
| --- | --- |
| file.reference | Specifies the file where the item change resides. This parameter is optional. If not specified, the item is read from the same file as the item being processed. |
| item-ID | Specifies the item to transfer control to. |

## Description

This command proves particularly
useful for generating form letters. It is possible to insert the name
and address of each recipient of the letter from a separate file.

A sselect statement is used to extract the
relevant data from the file and save it in a list. A series of readnext statements inserts the data into the text of the
letter. At the end of the letter, a .chain command
is used to restart the next letter. When the list is exhausted, the
Output processor stops.

## Example(s)

The item letter is reprocessed
until all stack data is exhausted.

```
u document letter
Dear .readnext
You may have won one million ($1,000,000) dollars.

Sincerely,
John Doe
.chain letter
```

## See also

- [.read command (Output processor)](https://d3codex.com/output-processor/dot-read-command-output-processor/)
- [.readnext command (Output processor)](https://d3codex.com/output-processor/dot-readnext-command-output-processor/)
- [Output processor commands](https://d3codex.com/output-processor/output-processor-commands/)
- [Output processor overview](https://d3codex.com/output-processor/output-processor-overview/)
- [sselect command](https://d3codex.com/access/sselect-command/)

---
Source: https://d3codex.com/output-processor/dot-chain-command-output-processor/ - part of the D3Codex reference.