Insert lines in a file starting from a specific line

Question

I would like to insert lines into a file in bash starting from a specific line.

Each line is a string which is an element of an array

line[0]=\"foo\"         


        

Answer 1

sed is your friend:

:~$ cat text.txt 
foo
bar
baz
~$ 

~$ sed '/^bar/\na this is the new line/' text.txt > new_text.txt
~$ cat new_text.txt 
foo
bar
this is the new line
baz
~$