# cfxdm - dm:fixcolumns

**dm:fixcolumns:** This cfxdm tag allows the user to remove the special characters like @,. (dot) etc from a column name. If there is a special character in between a column name (ex: First.Last), it replaces it with  (underscore) (Ex: First\_Last)

**dm:fixcolumns** syntax**:** It doesn't require any arguments. Just ingest the data into this tag using a pipe (-->)

In the below example, for a reference, we are going to use **Netflow data that is ingested into Elasticsearch** as an extension to query the data and ingest it into **dm:mergecolumns** to select specific columns using include/exclude or both together and merge them into a single target column.

Enter the below command to select **Netflow tag (#es:netflow**). (In this example, **es** name is used as a label to identify Elasticsearch extension and it's tags that are pointing to Netflow data index. The label is defined while adding the extension in cfxdx configuration file or through UI)

```
tag #es:netflow
```

![](/files/-MViGo-mzJmGerXr3d_1)

**Example 1:** Select three columns using the GET option from the Netflow tag.

Get the TCP protocol data from Elasticsearch Netflow tag (**#es:netflow**) for the last 1 hour and select the below three columns and ingest them into dm:fixcolumns tag to rename the names of the columns by replacing the special character (. (dot) with \_ (underscore).

**Source Columns:**

* flow\.client.addr
* flow\.server.addr
* flow\.service.port

**Output Columns:** (after replacing the special character ". (dot)" with "\_ (underscore)"

* flow\_client\_addr
* flow\_server\_addr
* flow\_service\_port

```
data * get `flow.client_addr`,`flow.server_addr`,`flow.service_port` --> dm:fixcolumns
```

![](/files/-MVyX6ltcSQ5BD1C3RlW)


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