sed replace line with multiline file or variable

Question

I'm retrieving a section from a file and want to replace a line in another file with this multi-line data. Currently I'm outputting to a file but would prefer to use a variable.

For instance

R 0x00007d04 0x70040000

[OVERWRITE_1]

C "- Starting Execution"

Becomes:

R 0x00007d04 0x70040000

W 0x00001118 0x0d1f4e3a
W 0x0000111c 0xa3795ac8 
W 0x00001120 0xc50e69d5

C "- Starting Execution"

Here is what I have:

START="R 0x00007fd0 0x00000000            # CSR:014 (CSRCID-OPT2)"
END="W 0x00007f80"
FILE=file.txt

#Retrieve text between sections above to variable
OUTPUT=$(sed -n "/^$START$/,/$END/ { /^$START$/d ; /$END/d ; /^$/d ; p }" 
$FILE)

echo "$OUTPUT" > tmp.txt

#This line currently appends after [OVERWRITE_1]
sed '/\[OVERWRITE_1\]/r tmp.txt' test.asm

Which outputs this:

R 0x00007d04 0x70040000

[OVERWRITE_1]
W 0x00001118 0x0d1f4e3a
W 0x0000111c 0xa3795ac8 
W 0x00001120 0xc50e69d5

C "- Starting Execution"

I know at this point I could remove the line but I feel like others might want to know this also and I haven't found a good solution.

Answer 1

Found solution here

With GNU sed:

Find line in file file.csv which contains find, append content (r) of file newline.txt and delete (d) line which contains find

START="R 0x00007fd0 0x00000000            # CSR:014 (CSRCID-OPT2)"
END="W 0x00007f80"
FILE=file.txt

#Retrieve text between sections above to variable
OUTPUT=$(sed -n "/^$START$/,/$END/ { /^$START$/d ; /$END/d ; /^$/d ; p }" 
$FILE)

echo "$OUTPUT" > tmp.txt

sed -e '/\[OVERWRITE_1\]/{r tmp.txt' -e 'd}' test.asm

Sed from variable instead of file :

START="R 0x00007fd0 0x00000000            # CSR:014 (CSRCID-OPT2)"
END="W 0x00007f80"
FILE=file.txt

#Retrieve text between sections above to variable
OUTPUT=$(sed -n "/^$START$/,/$END/ { /^$START$/d ; /$END/d ; /^$/d ; p }" 
$FILE)

echo "$OUTPUT" > tmp.txt

sed  "s/\[OVERWRITE_1\]/$OUTPUT/" test.asm

Note that we used double quotes instead of singles. But as found here there is a problem if you have special characters inside $OUTPUT (\\, & and /). Didn't find a good solution for this so I would keep the workaround with the file.