xz -cd foo.txz | wc -l

for i in *.txz; do echo $i; xz -cd $i | wc; done

• tar gzip compressed - .tgz
• tar bzip2 compressed - .tar.bz2, .tar.bz, .tbz
• tar xz compressed - .txz

tar cJvf foo.txz foo

cat foo.tgz | gzip -cd | xz > foo.txz

To do the other way around

cat foo.txz | xz -cd | gzip > foo.tgz

Ref:- http://lowfatdaemon.blogspot.com/2012/01/how-to-repackage-txz-to-tgz-slackware.html

tags | change compression algorithm of a tar archive

• Relative file names in a tar archive