Final answer:
To create a summary index, typically in a data platform like Splunk, the command before saving should be 'summary' to ensure the data is in a summarized form. After collecting and transforming the data with appropriate search and summary commands, you would save it to the summary index with the 'save' command.
Step-by-step explanation:
To create a summary index in Splunk—a platform for searching, monitoring, and analyzing machine-generated big data—the command that must be used before saving is summary. However, the context of this may vary depending on the specific platform or search tool you are referring to. In general, when working with data indexing, ensuring that your data is properly summarized before saving it to an index is crucial for data retrieval and analysis efficiency.
After running the necessary search commands that generate the data you want to summarize, you would typically use a summarizing function or command like stats, chart, timechart, or a similar aggregation command to transform the data into a summary form. Once the data is summarized, you can then use the save command or equivalent function to store the results in your summary index for later retrieval.