Removing text watermark from PDF

Following this guide, the solution for me was:

1. Fix your PDF, just in case:
   

   pdftk original.pdf output fixed.pdf

2. Uncompress your PDF for text manipulation:
   

   pdftk fixed.pdf output uncompressed.pdf uncompress

3. Remove text watermark with SED:
   

   sed "s/Wow! eBook <WoweBook.Com>/ /g" uncompressed.pdf > unwatermarked.pdf

4. Compress the edited PDF:
   

   pdftk unwatermarked.pdf output compressed.pdf compress

As usually, I had trouble using SED.
It turned out that sed -e "s/Wow! eBook <WoweBook.Com>/ /" did not work for me, but somehow the one without the -e option and with the /g flag did.