You can use tar -tvf to show the contents of a tar file.

tar -tvf  filename.tgz

You can extract a portion of the archive with

tar -zxvf filename.tgz path/inside/file -C destination/path

For instance, if I have a tar backup of my /home directory, and I need to extract a file out of the tarred Downloads to my current Downloads directory, I can do

tar -zxvf home.tgz home/incredigeek/Downloads/slack.deb ~/Downloads

https://www.cyberciti.biz/faq/list-the-contents-of-a-tar-or-targz-file/

https://stackoverflow.com/questions/24057301/bash-extract-only-part-of-tar-gz-archive