Changing A File Extension

If you change a file like a .mp3 one, let's say, to a .123 one, so that it can't be opened, is there any way to recover the orginal file?

Renaming it back to the original extension?

Erm.. perhaps I've misunderstood the question but if you've simply renamed a file extension from, say, .aaa to .bbb, changing it back to .aaa will return it to its original file association group.

the association is with extension, not with the file. You can change how many time you want, just returning to correct one before use it

It is possible to corrupt a file like that though. So, make sure you have a backup...

Say you have a .exe and then rename it .123
Since .123 is actually a lotus spreadsheet... someone can open it with a spreadsheet ap.
Lotus won't be able to understand it and will ask the user to convert it.
If they save after the conversion... and then you rename it back .exe, it will be corrupt.

I've played around a bit just seeing what would happen if I did this, or that...
I get bored sometimes...

So, if you rename a file extention, then don't do anything to it again before renaming it back... it will be fine.

I know I have to do that sometimes when sending emails.

Since everyone started stripping .zip files (thanks to recent viruses) I can rename the file to a .zif and just tell whoever I'm mailing to rename it back to .zip.

I do that too, since our mail servers(or firewall) strip the *.mpg, *.avi, *.zip, etc. It was the most obvious thing to do, in my mind. Even had to make a little text file explaing to my jughead friends how to get the file back to the original extension to play it or what not. I usually rename to .aaa or just no extension at all. It's kind of annoying to do that all the time, but at least the files get through this way.

Phish:

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Since everyone started stripping .zip files (thanks to recent viruses) I can rename the file to a .zif and just tell whoever I'm mailing to rename it back to .zip.

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Thanks for telling the virus authors in public how to socially engineer my (L)users and bypass my firewall mail protection..... ;) They didn't get the "don't put the password into password protected zips" bit of advice so I had to block them, (I could tell by the number of dumb questions). :rolleyes:

What you don't want to be doing is rename an .exe file to something like .txt. I mean, you could want to - but it would obviously be a large frigging text file. Point is, MS decided it's not a big issue that CMD.EXE executes any file that is an executable, even if it doesn't have the executable extension. Unfortunately this poses a greater security risk then most care to admit...

As for your question... do you mean can somebody realize what file it is, originally? They could probably break it down using a hex editor and try to do a look-up on the header of the file, in order to detect what it could be. MP3s usually have the title in the first few bytes, .avi containst the line '.avi' close to the top, and .mpg might require a bit more to find - but nothing difficult. Of course for different files there are different situations...

If you only meant the file extension change, I guess you should also read up on file systems and their allocation tables, in order to get maybe a better understanding of what exactly filenames are and everything related.

TS you cant tell me you allow .zif files threw your firewall. i know better than that.

TheFueley you could always uu encode it and send it as a txt attachment then tell the recipiant to change the extention of the attachment to uue. the icon will instantly change to that of a zip file and winzip will be able to open it and what you've sent will be inside the zip.

i think what he is asking, is if you change the filename extention to .123 for example, is there a way to tell WHAT the original extention was?? in otherwords, if i change matrix.zip to matrix.mpg -
obviously windows media player wont open it, but is there a way to discover what it was originally??? is that what you were asking??