It might be easiest to uncompress the PDF with pdftk and then just use perl for the substitution: 
   pdftk old.pdf output new.pdf uncompress
   perl -pi -e 's/oldstring/newstring/g' new.pdf

[download]
If you want to recompress the file, 
   pdftk new.pdf output new_compress.pdf compress

[download]

In reply to Re: Edit PDF Text by jbullock35
in thread Edit PDF Text by avik

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