Replace a word with multiple lines using sed?
You can do this with AWK using variable substitution. We can set a variable in AWK using -v, and then use AWK's gsub function to substitute all occurrences of a regular expression with that variable.
For example, if the file test has the following contents ...
foobarblah _data_and_data_foo_data_ foobar _data_ again... and the Bash variable $DATA is ...
12345... then awk -v r=$DATA '{gsub(/_data_/,r)}1' test replaces all occurrences of the regular expression _data_ in the file test with the contents of $DATA, resulting in the following:
foobarblah 12345and12345foo12345 foobar 12345 again