Doing the job I do, sometimes I get people phoning me up saying they can’t open such-a-such file. Now there are a few obvious reasons why this could be - normally because the user doesn’t have the software installed on their PC to view the file. Maybe it’s because they have an older version of the software. There is also a classic problem, where someone has been emailed a link to the file, rather than the file itself.
However, in my experience, most of these problems can be sorted out with a file analyser. I recently had this problem (about half an hour ago) and what I really wanted to know was - is the file actually what the extension is, and if it was, I would be able to determine from that if the file was really corrupt.
I found a few file analysers. A DOS one I had used before “File Analyzer” and one I hadn’t, which has a horrible Windows 9x interface called “What Format” but both of these don’t appear to have been updated since 2002 - but are perfectly usable with the more common file types. I found a newer nagware analyser called “File Find for Windows” which says it can recognise 2,338 different types of files.
I had a pdf file which a user said they couldn’t open, so I fired it through all 3 programs. All 3 correctly identified it as a pdf file - and I even removed the extension to double check the programs weren’t cheating!! The upshot was that the file I wanted to check was definitely a pdf file, and it definitely was corrupt.. =)
I also tested a few other files (again after removing the extensions) and here are the results (red means a fail, whilst green means it was detected correctly):
Type: .ra (Realplayer audio file)
FA WhatFormat FileFind
Type: .psd (Photoshop Image)
FA WhatFormat FileFind
Type: .skr (PGP Private Keyring)
FA WhatFormat FileFind
Type: .ost (Outlook offline folders file)
FA WhatFormat FileFind
Type: .img (Atari ST ROM dump)
FA WhatFormat FileFind
Type: .pyc (Juice Plugins file)
FA WhatFormat FileFind
To be honest, the last two file types I really didn’t expect any of the programs to get (which was the case). It was, however, interesting that only FileFind got the ost file, which I think is mainly due to the age of the other two programs. Also that both WhatFormat and FileFind both got the PGP secring file, whilst FA didn’t, even though that file format has been around for a long time.