My wife received a file named Voucher.pdf from a motel we were going to stay at. When she attempted to view it her email client on her iPhone failed to open it. She forwarded it to me and I got the same result on my Samsung Galaxy S2 (yes we are a Apple/Android divided household).

I downloaded the file onto my laptop and opened it in vi and found that it had what I call gobbledeegook as follows:

So apparently the PDF file had been uuencoded and attached straight to the email client but without the proper headers and such so as to inform the email client that it needs to be decoded back into PDF format before it could be opened.

So after downloading voucher.pdf I simply installed sharutils (sudo yum install sharutils on Redhat, sudo apt-get install sharutils on Debian) and then ran:

uudecode voucher.pdf -o test.pdf

and I now had a properly formatted pdf file...