I found this link on how to open tgz in one step.gzip -dc target.tar.gz | tar xf -What does the '-' mean?
What does - mean as an argument to a command?
command line;tar
It's a common convention to use - in a filename argument to mean stdin or stdout; tar follows the same convention. From the man page:   -f, --file [HOSTNAME:]F          use archive file or device F (default -, meaning stdin/stdout)