Work with PDF files from a command line
If you want to edit a PDF, such as a find and replace, you can uncompress it with pdftk.
Install pdftk
$ sudo apt-get install pdftk
Uncompress the PDF.
$ pdftk compressed.pdf output uncompressed.pdf uncompress
Work on the PDF with whatever text editor you like.
Then just recompress it with,
$ pdftk uncompressed.pdf output newcompressed.pdf compress