Adobe Acrobat Reader 6.0 and above allow searching a collection of PDF files.

Using a search program to search for a text in a collection of files of different types, it may or may not be possible to also search PDF files, depending on the program. This is because the text is stored in coded form, and a program searching for some text must interpret the code and search the result, not just search the code.

Search programs that do not work include that of Windows XP and Agent Ransack. However, for searching the Web, some search engines, such as Google and Yahoo!, include PDF files in searches. The option to view the PDF in HTML format is also commonly offered (this conversion does not include images).

Mac OS X, having PDF as a core element of the operating system, fully supports searching PDF files with the Preview application, used to view PDF files. The Spotlight feature in Mac OS X v10.4 extends this ability across the whole operating system, allowing information in PDF files (as well as almost all others) to be found from a single search box.

On the Windows platform, text in PDF files can be searched using Google Desktop Search and also Windows Desktop Search when installed with an appropriate iFilter available from Adobe.

On the Lnux and Unix platforms (and experimental Windows ports), the Beagle provides functionality similar to Apple’s Spotlight, including text searching through the content of PDFs. The related program Dashboard (not to be confused with Apple’s OS X Dashboard) also looks inside PDFs.