Use Regular Expressions to Search Through Any File Supported by Windows Search

What Is IFilter?

When Microsoft created the Windows Search feature that allows you to search through files in Windows Explorer, Microsoft also created a system that allows 3rd party developers to add support for additional file formats. This system is known by its technical name IFilter. If a company creates a proprietary file format, they can provide an IFilter that their customers can install. Then Windows Search can search through the text in files saved in that company's proprietary format.

Microsoft themselves also provide a range of IFilter implementations. Windows 2000 and later include IFilters for the binary Microsoft Office formats: DOC, XLS, and PPT. Office 2007 and later install IFilters for the new Open XML formats: DOCX, XLSX, and PPTX. OpenOffice includes an IFilter for the OpenDocument format. The Microsoft Filter Pack is a separate download which provides IFilter support for various Microsoft file formats, including those used by Office 2007 and 2010, without depending on the software that creates those file formats.

Using IFilter with PowerGREP

PowerGREP can use any IFilter that you have installed on your computer. Because there are advantages and disadvantages to using IFilter, you can tell PowerGREP for exactly which file types you want to use IFilter and/or for exactly which file types you don't want to use IFilter.

By default, PowerGREP does not use IFilter for plain text files. E.g. Windows ships with an IFilter for HTML files that extracts the text without the HTML tags from the file. Thus Windows Search only searches the actual text in web pages, and never the HTML tags. PowerGREP searches HTML files entirely, including all the HTML tags. This allows you to work with both the contents of web pages as well as their formatting. If PowerGREP determines that a file is a binary file rather than a plain text file, then by default PowerGREP will use the IFilter for that file, if one is installed on your computer.

PowerGREP does not have any control over the way the IFilters installed on your computer work. It can only choose to use them or not. Since some IFilters definitely work better than others, PowerGREP gives you fine-grained control over which files you want to search using IFilter, and which you want to search directly.

Since Windows Search can only search through files, Microsoft made the IFilter system read-only. If you configure PowerGREP to use IFilter for certain file types then PowerGREP cannot make changes to those files. But PowerGREP can use all its regular expressions and other capabilities on files decoded with IFilter.

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Perl, Java and .NET compatible regular expressions
Extensive text encoding support: Windows and DOS code pages, Unicode, ISO-8859, ECBDIC, KOI8, etc.
Search MS Word and PDF documents
Search Excel, Lotus 1-2-3 and Quattro Pro spreadsheets
Search through OpenOffice documents, spreadsheets, etc.
Search through and move files in and out of ZIP archives

Page URL: http://www.powergrep.com/ifilter.html
Page last updated: 15 November 2012
Site last updated: 02 May 2013