Deleting text between two strings using sed -

i trying delete of text between 2 strings in number of txt files, including strings themselves.

the strings subject: , body:

this have been using:

sed '/subject:/,/body:/d' *.txt 

it appears run without issue, there no changes files upon completion.

add -i flag modify files in place: sed -i '/subject:/,/body:/d' *.txt