I have a tar file that ends with .b and I don't know how to open it. Neither in windows, neither Linux I've been successful to open it.


Another tar that ends with .a could easily be opened in Windows


What's is the difference? How can I possibly open the .b tar?

This is from an Android OS image - a nandroid backup. .a consists of all the apps and hopefully .b consists of pictures

  • It might be compressed; if you use the file command, it can give more information: file data.ext4.tar.b Apr 7, 2016 at 22:22
  • @ThomasDickey - this was returned: data.ext4.tar.b: data Apr 7, 2016 at 22:25
  • Do you also have a data.ext4.tar file?
    – Ryan
    Apr 9, 2016 at 1:48

3 Answers 3


According to How do you extract an App's data from a full backup made through “adb backup”?, that is a compressed tar-file using the deflate method. The accepted answer in that thread points to a program which you might use: nelenkov/android-backup-extractor

There also is this, which might work: Android Backup Extractor.

The deflate method is one of those which web servers might return, but is less used than gzip. The file program may not know about it.

Further reading:

  • thanks but I did the backup with clockworkmod and all tar-files and .img's are wrapped together in a .zip-file Apr 7, 2016 at 22:32

It sounds like something split the file. When you try to un-tar the .a file does it abort early? That's a hint that it is split. Is the .a file 4GB? That's another hint. Try concatenating the files on a machine that can handle large files...

cp myfile.tar.a myfile_full.tar
cat myfile.tar.b >> myfile_full.tar
tar xvf myfile_full.tar
  • thanks, i've a dual boot - right now on Windows - later on i'll try this. Apr 8, 2016 at 10:27

Whats is the difference? How can I possibly open the .b tar?

As far as I can tell, either ClockworkMod or TAR splits the backup into several files. If you're able to open the data.ext4.tar.a file, it might be because it has the TAR file headers at its start while data.ext4.tar.b does not. To get to the data in data.ext4.tar.b, you probably have to combine the split archive files into one single archive file.

On Linux, try to combine all of your TAR files using one of the following commands:

$ cat data.ext4.tar.a data.ext4.tar.b > data-combined.tar
$ cat data.ext4.tar* > data-combined.tar

Then try to open data-combined.tar as you would any other TAR file.

Or, if you're doing this on Windows, try one of the following commands:

> copy /b data.ext4.tar.a + data.ext4.tar.b data-combined.tar
> copy /b data.ext4.tar* data-combined.tar

Then try to open data-combined.tar as normal.

In both cases, here are what the commands do. The first command will combine data.ext4.tar.a and data.ext4.tar.b into data-combined.tar. The second command will combine any file in the current directory that begins with data.ext4.tar into data-combined.tar, so it can be used if you have more than the two files listed.


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