[PATCH 1/3] parse-opt: migrate fmt-merge-msg.

@@ -5,8 +5,10 @@
 #include "revision.h"
 #include "tag.h"
 
-static const char *fmt_merge_msg_usage =
-	"git fmt-merge-msg [--log] [--no-log] [--file <file>]";
+static const char * const fmt_merge_msg_usage[] = {
+	"git fmt-merge-msg [--log|--no-log] [--file <file>]",
+	NULL
+};
 
 static int merge_summary;
 

@@ -347,38 +349,32 @@ int fmt_merge_msg(int merge_summary, struct strbuf *in, struct strbuf *out) {
 
 int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 {
+	const char *inpath = NULL;
+	struct option options[] = {
+		OPT_BOOLEAN(0, "log",     &merge_summary, "populate log with the shortlog"),
+		OPT_BOOLEAN(0, "summary", &merge_summary, "alias for --log"),
+		OPT_STRING('F', "file",   &inpath, "file", "file to read from"),
+		OPT_END()
+	};
+
 	FILE *in = stdin;
 	struct strbuf input, output;
 	int ret;
 
 	git_config(fmt_merge_msg_config, NULL);
-
-	while (argc > 1) {
-		if (!strcmp(argv[1], "--log") || !strcmp(argv[1], "--summary"))
-			merge_summary = 1;
-		else if (!strcmp(argv[1], "--no-log")
-				|| !strcmp(argv[1], "--no-summary"))
-			merge_summary = 0;
-		else if (!strcmp(argv[1], "-F") || !strcmp(argv[1], "--file")) {
-			if (argc < 3)
-				die ("Which file?");
-			if (!strcmp(argv[2], "-"))
-				in = stdin;
-			else {
-				fclose(in);
-				in = fopen(argv[2], "r");
-				if (!in)
-					die("cannot open %s", argv[2]);
-			}
-			argc--; argv++;
-		} else
-			break;
-		argc--; argv++;
+	argc = parse_options(argc, argv, options, fmt_merge_msg_usage, 0);
+	if (argc > 0)
+		usage_with_options(fmt_merge_msg_usage, options);
+
+	if (!inpath || strcmp(inpath, "-"))
+		in = stdin;
+	else {
+		fclose(in);
+		in = fopen(argv[2], "r");
+		if (!in)
+			die("cannot open %s", argv[2]);
 	}
 
-	if (argc > 1)
-		usage(fmt_merge_msg_usage);
-
 	strbuf_init(&input, 0);
 	if (strbuf_read(&input, fileno(in), 0) < 0)
 		die("could not read input file %s", strerror(errno));

@@ -387,6 +383,6 @@ int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 	ret = fmt_merge_msg(merge_summary, &input, &output);
 	if (ret)
 		return ret;
-	printf("%s", output.buf);
+	write_in_full(STDOUT_FILENO, output.buf, output.len);
 	return 0;
 }