How to replace a multi line string in a bunch files

Question

#!/bin/sh
old=\"hello\"
new=\"world\"
sed -i s/\"${old}\"/\"${new}\"/g $(grep \"${old}\" -rl *)

The preceding script just work for single line text

Answer 1

You could use perl or awk, and change the record separator to something else than newline (so you can match against bigger chunks. For example with awk:

echo -e "one\ntwo\nthree" | awk 'BEGIN{RS="\n\n"} sub(/two\nthree\n, "foo")'

or with perl (-00 == paragraph buffered mode)

echo -e "one\ntwo\nthree" | perl -00 -pne 's/two\nthree/foo/'

I don't know if there's a possibility to have no record separator at all (with perl, you could read the whole file first, but then again that's not nice with regards to memory usage)