Use the following command:
```
$ GREP_SED="^\(\s\+master_type: \)true" \
  && grep -rl "${GREP_SED}" test/integration/ \
  | xargs sed -i -e "/${GREP_SED}/s//\1str/"
```
		
	
Use the following command:
```
$ GREP_SED="^\(\s\+master_type: \)true" \
  && grep -rl "${GREP_SED}" test/integration/ \
  | xargs sed -i -e "/${GREP_SED}/s//\1str/"
```