+#define diff_trivial_usage \
+ "[-abdiNqrTstw] [-L LABEL] [-S FILE] [-U LINES] FILE1 FILE2"
+#define diff_full_usage \
+ "Compare files line by line and output the differences between them.\n" \
+ "This diff implementation only supports unified diffs.\n\n" \
+ "Options:\n" \
+ "\t-a\tTreat all files as text\n" \
+ "\t-b\tIgnore changes in the amount of whitespace\n" \
+ "\t-d\tTry hard to find a smaller set of changes\n" \
+ "\t-i\tIgnore case differences\n" \
+ "\t-L\tUse LABEL instead of the filename in the unified header\n" \
+ "\t-N\tTreat absent files as empty\n" \
+ "\t-q\tOutput only whether files differ\n" \
+ "\t-r\tRecursively compare any subdirectories\n" \
+ "\t-S\tStart with FILE when comparing directories\n" \
+ "\t-T\tMake tabs line up by prefixing a tab when necessary\n" \
+ "\t-s\tReport when two files are the same\n" \
+ "\t-t\tExpand tabs to spaces in output\n" \
+ "\t-U\tOutput LINES lines of context\n" \
+ "\t-w\tIgnore all whitespace\n"
+