save only some pdf pages from a pdf

You can use Okular, of course: print to file -> the pages you want. But thus you get an image pdf. If you want keep a text pdf, you can use a program like PdfArranger, which allows to save (only) the pages you want from a whole pdf, keeping them as searchable pdf (text).

re-ocr a pdf with Adobe

You have to 1) save the old searchable pdf to tiff images (as many as the pages), 2) ocr the tiff images to a searchable pf 3) combine the new multiple pdf to one pdf.

OpenOffice: crash on pdf export

Può succedere (fa arrabbiare non saper spiegare esattamente perché, ma è così).
Due le soluzioni, in Linux:

  • loggarsi come root e allora export as PDF funziona senza problemi
  • usare il comando print -> to file

Si tratta di ripieghi, daccordo, ma almeno provvisoriamente servono 😉