[El Gato]

If the pdf is in a recent version of Adobe Acrobat, you should be able to cut and paste text.

But the document was probably scanned as an image, so no matter what the version of Acrobat, it can't be handled as text. If you create a PDF from some other source, say a Word document or html file, then you have access to the text.

[Fedora]

Yes, that won't work for scanned images.