To reach this options page, select File > Report... > UNIX diff
This reporter is used to create reports like those created by the popular UNIX diff program. The reporter supports the creation of edit script reports (the default diff output format), context-diff reports (diff's -c option), and unified-diff reports (diff's -u option).
Please note that the output of a diff-style report from Merge will not be the same as a report generated by the real diff program. Merge and diff use different algorithms to calculate the changes between files. Although they will agree about many changes, there will be some (or many) cases where they won't.
Use edit script format
Choose this option to generate an edit script report for the file comparison. The script contains the steps that you would need to perform to convert the first file into the second file.
Use context format
This format includes several lines of context around each block of changed, inserted, or removed lines in the report.
Use unified format
This format is a more compact form of the context report.
# lines of context
This value in this field is used by Merge for context and unified format reports.
Context and unified format reports surround each block of changed, inserted, and removed lines in the report with a number of unchanged lines. The contents of this field determines how many unchanged lines are included.
The unchanged lines provide you with some visual context for the change so that it is easier to locate the change in the compared files. Some patch programs can use the context information in the generated reports to convert one file into the other, even when modifications have been made to the file since the report was created. Such programs typically require at least three lines of context to operate reliably.