[NTLUG:Discuss] untar-ing without creating one level of directories

[Richard]

What is the term used to untar something without creating that first 
directory structure level?

For instance, when I'm untar-ing  pmwiki-latest.tgz,  I want the files 
in the first directory structure stored in that tgz(pmwiki-Ver.si.on) to 
go directly into the current directory and not into a subdirectory which 
causes me to have to do a 'mv pmwiki-Ver.si.on/* .'

While I sometimes want that functionality, it'd be nice to be able to 
turn it off on occasion.

For that matter, is there a way to redirect tar to extract files into an 
alternate path?

-- 
Richard