Grep everything between two pattern if match not found

Shell Programming and Scripting
1

I need to help to work this

Print everything between 2 patterns if grep is not found the search word
example

Detroit
orange
cat
bat 
rat
apple

sed  -n "/Detroit,/apple/p" d |grep  chicago

output would be

Detroit
orange
cat
bat 
rat
apple
2

Not sure if I understood this, but what do you want to display if grep **does** find something in the file?
I assume in that case you want to show the output of grep.
Is the following what you're looking for?

$ 
$ cat f34
Detroit
orange
cat
bat 
rat
apple
$ 
$ 
$ # grep doesn't find anything in the file; show the output of sed
$ 
$ grep chicago f34 || sed -n '/Detroit/,/apple/p' f34
Detroit
orange
cat
bat 
rat
apple
$ 
$ 
$ # grep does find something in the file; show the output of grep, do not show the output of sed
$ 
$ grep cat f34 || sed -n '/Detroit/,/apple/p' f34
cat
$ 
$