As far as I know `tr` only works with single characters and _". "_ is a string not a character, so it is possible to do what you want by using `sed` or `awk`, for example:
sed -e "s/\. /\
/g" file.txt > out.txt
As far as I know `tr` only works with single characters and _". "_ is a string not a character, so it is possible to do what you want by using `sed` or `awk`, for example:
sed -e "s/\. /\
/g" file.txt > out.txt