# combine > Perform set operations on lines of two files. > The order of the output lines is determined by the order of the lines in the first file. > See also: `diff`. > More information: . - Output lines that are in both specified files: `combine {{path/to/file1}} and {{path/to/file2}}` - Output lines that are in the first but not in the second file: `combine {{path/to/file1}} not {{path/to/file2}}` - Output lines that in are in either of the specified files: `combine {{path/to/file1}} or {{path/to/file2}}` - Output lines that are in exactly one of the specified files: `combine {{path/to/file1}} xor {{path/to/file2}}`