For example I have this text:

<<<<<<<<< <<source_dir>>
tesst
<<<<<<<<< <<target_dir>>
tes23442141
<<<<<<<<<
good
safasf

<<<<<<<<< <<source_dir>>
tesst241241
<<<<<<<<< <<target_dir>>
tes23442141
<<<<<<<<<

safasfas

And section is

<<<<<<<<< <<source_dir>>
[any text -> first text]
<<<<<<<<< <<target_dir>>
[any text -> second text]
<<<<<<<<<

And I want replace all this section to only first text

For example output must be:

tesst
good
safasf

tesst241241

safasfas

I have this sed :

sed -e ':a;N;$!ba;s#<<<<<<<<< <<source_dir>>n(.*)n<<<<<<<<< <<target_dir>>.*<<<<<<<<<#1#g' "$target_file"   

But as output I have:

tesst
<<<<<<<<< <<target_dir>>
tes23442141
<<<<<<<<<
good
safasf

<<<<<<<<< <<source_dir>>
tesst241241

safasfas

And question how I can fix it?)
I understand the problem but I don’t understand how to do it>
Please help me!