mod_sed - Apache HTTP Server Version 2.4

Apache HTTP Server Version 2.4

Apache > HTTP Server > Documentation > Version 2.4 > Modules

# Apache Module mod_sed

Available Languages: en | fr

Description: | Filter Input (request) and Output (response) content using `sed` syntax
Status: | Experimental
Module Identifier: | sed_module
Source File: | mod_sed.c sed0.c sed1.c regexp.c regexp.h sed.h
Compatibility: | Available in Apache 2.3 and later

### Summary

`mod_sed` is an in-process content filter. The `mod_sed` filter implements the `sed` editing commands implemented by the Solaris 10 `sed` program as described in the manual page. However, unlike `sed`, `mod_sed` doesn't take data from standard input. Instead, the filter acts on the entity data sent between client and server. `mod_sed` can be used as an input or output filter. `mod_sed` is a content filter, which means that it cannot be used to modify client or server http headers.

The `mod_sed` output filter accepts a chunk of data, executes the `sed` scripts on the data, and generates the output which is passed to the next filter in the chain.

The `mod_sed` input filter reads the data from the next filter in the chain, executes the `sed` scripts, and returns the generated data to the caller filter in the filter chain.

Both the input and output filters only process the data if newline characters are seen in the content. At the end of the data, the rest of the data is treated as the last line.

A tutorial article on `mod_sed`, and why it is more powerful than simple string or regular expression search and replace, is available on the author's blog.

### Topics

- Sample Configuration
- Sed Commands

### Directives

- Comments

## Sample Configuration

### Adding an output filter

    # In the following example, the sed filter will change the string
    # "monday" to "MON" and the string "sunday" to SUN in html documents
    # before sending to the client.
    <Directory "/var/www/docs/sed">
        AddOutputFilter Sed html
        OutputSed "s/monday/MON/g"
        OutputSed "s/sunday/SUN/g"
    </Directory>

### Adding an input filter

    # In the following example, the sed filter will change the string
    # "monday" to "MON" and the string "sunday" to SUN in the POST data
    # sent to PHP.
    <Directory "/var/www/docs/sed">
        AddInputFilter Sed php
        InputSed "s/monday/MON/g"
        InputSed "s/sunday/SUN/g"
    </Directory>

## Sed Commands

Complete details of the `sed` command can be found from the sed manual page.

`b`
  Branch to the label specified (similar to goto).
`h`
  Copy the current line to the hold buffer.
`H`
  Append the current line to the hold buffer.
`g`
  Copy the hold buffer to the current line.
`G`
  Append the hold buffer to the current line.
`x`
  Swap the contents of the hold buffer and the current line.

## InputSed Directive

Description: | Sed command to filter request data (typically `POST` data)
Syntax: | `InputSed sed-command`
Context: | directory, .htaccess
Status: | Experimental
Module: | mod_sed

The `InputSed` directive specifies the `sed` command to execute on the request data e.g., `POST` data.

## OutputSed Directive

Description: | Sed command for filtering response content
Syntax: | `OutputSed sed-command`
Context: | directory, .htaccess
Status: | Experimental
Module: | mod_sed

The `OutputSed` directive specifies the `sed` command to execute on the response.

Available Languages: en | fr

## Comments

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