> For the complete documentation index, see [llms.txt](https://docs-v3.toucantoco.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs-v3.toucantoco.com/data-management-in-datahub/datasets-in-toucan/preparing-data/overview-of-youprep-tm/column-header/duplicate-column.md).
# Duplicate column
The Duplicate column step enables you to duplicate a specific column. The duplicated column will be added to the end of the dataset.
### Step parameters
* `Duplicate column...` **column(string)\***: the column to duplicate
* `new column name` **string\***: Set a name for the duplicated column.
### Example
**Input**
{% hint style="warning" %}
an error will be raised if you try to set a name that is already used for another column.
{% endhint %}
---
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