Q:

Can I discover the format of archive? 

Not long I have decided to make a compress of my archives .deb / tar.gz, on only one archive.  No problem I compress, and I used split command to break that archive in many parts to (upload - backup) and works fine, but the problem is, I forgot what the format of the compress that I used.  And now, I don't know how to join the parts.  I can anything to do? 

A:

Join file:
cat split1 split2 split3 > myfile

To find out archive format, you can use file(1). 
For example:
housezet@arch: ~
$ file ufw-0.33
ufw-0.33: gzip compressed data, from Unix, last modified: Sat Aug 18 06:12:49 2012

