## lets archive 'dir' directory
$ ls -l
total 0
drwxr-xr-x 2 1000 1000 460 Jun 28 09:05 dir
$ du -sh dir
5,2M    dir


$ tar -c -f archive.tar dir
$ ls -l
total 5220
-rw-r--r-- 1 1000 1000 5345280 Jun 28 09:11 archive.tar
drwxr-xr-x 2 1000 1000     460 Jun 28 09:05 dir

## compress resulting .tar archive
$ gzip -k archive.tar
$ ls -l
total 5896
-rw-r--r-- 1 1000 1000 5345280 Jun 28 09:11 archive.tar
-rw-r--r-- 1 1000 1000  690193 Jun 28 09:11 archive.tar.gz
drwxr-xr-x 2 1000 1000     460 Jun 28 09:05 dir

## one can do it in one go telling 'tar' to use compressor
$ tar --help
$ grep -E 'gzip|use-compress-program'
  -I, --use-compress-program=PROG
  -z, --gzip, --gunzip, --ungzip   filter the archive through gzip


$ tar -c -z -f archive.tgz dir
$ ls -l
total 6572
-rw-r--r-- 1 1000 1000 5345280 Jun 28 09:11 archive.tar
-rw-r--r-- 1 1000 1000  690193 Jun 28 09:11 archive.tar.gz
-rw-r--r-- 1 1000 1000  690181 Jun 28 09:11 archive.tgz
drwxr-xr-x 2 1000 1000     460 Jun 28 09:05 dir

$ tar -c -Igzip -f archive.tgz dir
$ ls -l
total 6572
-rw-r--r-- 1 1000 1000 5345280 Jun 28 09:11 archive.tar
-rw-r--r-- 1 1000 1000  690193 Jun 28 09:11 archive.tar.gz
-rw-r--r-- 1 1000 1000  690181 Jun 28 09:11 archive.tgz
drwxr-xr-x 2 1000 1000     460 Jun 28 09:05 dir

$ tar -c '-Igzip -9' -f archive.tgz dir
$ ls -l
total 6540
-rw-r--r-- 1 1000 1000 5345280 Jun 28 09:11 archive.tar
-rw-r--r-- 1 1000 1000  690193 Jun 28 09:11 archive.tar.gz
-rw-r--r-- 1 1000 1000  659400 Jun 28 09:11 archive.tgz
drwxr-xr-x 2 1000 1000     460 Jun 28 09:05 dir

## here is a script
$ cat tar1.sh
#!/bin/sh -x

ls -l
du -sh dir

tar -c -f archive.tar dir
ls -l

gzip -k archive.tar
ls -l

tar --help | grep -E "gzip|use-compress-program"

tar -c -z -f archive.tgz dir
ls -l

tar -c -I'gzip' -f archive.tgz dir
ls -l

tar -c -I'gzip -9' -f archive.tgz dir
ls -l