Repair gzipped tar

I have a pretty large(50Gb) tar.gz file that I can't untar anymore. Error that I am getting is this:

gzip: stdin: not in gzip format
tar: Child returned status 1
tar: Error is not recoverable: exiting now

Is there any way to repair broken tar.gz?

UPDATE: Output of file command:

$ file projects.tgz
projects.tgz: POSIX tar archive (GNU)

2 Answers

Your file is an uncompressed tarball. The extension .tgz is misleading, you might want to give the file a better extension, like .tar:

mv projects.tgz projects.tar

You've possibly tried to extract the file by running:

tar xzvf projects.tar

But the correct way to extract the tarball is:

tar xvf projects.tar

Options explained:

x: extract
z: GZip compressed (which is not the case in your file, so it should be removed for now)
f: file (required next argument to be the filename of the archive)
v: Be verbose (show file names while extracting).

See the manual page on tar for more information about this command.

Rename projects.tgz to projects.tar. Then you will be able to untar the archive via Nautilus for instance.