How to grep a multiple text line section from a beginning text pattern to an ending pattern?

Question

For example text below , in Linux, how to get the section below from the "will be installed" to the text before "Suggested packages".

Use 'apt-get autoremove' to remove it.
The following extra packages will be installed:
   python3-decorator python3-simplegeneric
Suggested packages:
  ipython3-notebook ipython3-qtconsole python3-zmq
The following NEW packages will be installed:
  ipython3 python3-decorator python3-simple-generic
0 upgraded, 3 newly installed, 0 to remove and 13 not upgraded.

And the output to get is simply " ipython3-notebook ipython3-qtconsole python3-zmq" , WITHOUT the beginning and ending pattern.

Answer 1

Using GNU sed rather than grep:

$ gsed -n '/The following extra packages will be installed:/{:a;n;/Suggested packages:/q;p;ba}' text

When the line containing the text The following extra packages will be installed, the sed editing script will create a label called a (to jump back to later) and then read the next line (n). If that line contains the text Suggested packages: the script will terminate (q), otherwise it prints the line (p) and branches back to the label previously created (ba) which reads the next line, etc.