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/"
```