Hi again…
I’m trying to do this this kind of backup making full and differentials using this link 
so… if I do 
ssh user@desthost “( nc -l 9999 > /data/backups/backup.xbstream & )” && xtrabackup –backup –stream=xbstream ./ | nc desthost 9999
works very good! for full…
but if I do differentials. I need the xtrabackup_checkpoint wich is inside of backup.xbstream.
so my question is: How can I get that file from the binary “backup.xbstream” without extract all things. ???
or make a copy of that file BEFORE it go to into binary file.

I need that file to get the information of Log Sequencer Number in order to create the new differential backup 
thanks for your support.

You need to unpack the whole stream to read that file. Xbstream by itself does not provide compression, so you are not getting any space savings if you store files in steam file or unpacked.

Thanks … for the info.