Replace text between two lines with contents of a file stored in a variable in sed

Question

Let\'s say I have a file called original.txt with this content:

red
blue
water
food
tree

Answer 1

I see you asked for sed help, but ex handles this use-case in a bit more straightforward way. This may work for you (in a shell script):

ex original.txt << EOF_EX
/blue/+1,/gray/-1 d
r new.txt
w edited.txt
q!
EOF_EX

The above opens original.txt for editing, deletes the range of lines one past blue through one before gray, reads the file new.txt, and writes out file edited.txt.

Result:

$ cat edited.txt
red
blue
gray
green
black
yellow
purple
white

Alternatively you could replace "w edited.txt" with "wq" and it would save the changes in the original.txt file.

Also, notice the +1 and -1 syntax in the range, which can be very handy. For example if you had wanted to also remove the range-bounding patterns, "blue" and "gray" you could remove the +1 and -1 and it would mean delete the range, including the range-boundary patterns.