Add an -o filename option to have the output written to a file.

This option is present on most uuidgen(1) implementations even
though normal file redirection can be used to achieve the same.

Submitted by: Hiten Pandya <hiten@unixdaemons.com>

2 files changed, 22 insertions, 6 deletions

diff --git a/bin/uuidgen/uuidgen.1 b/bin/uuidgen/uuidgen.1
index 58b4a59..f97c6a8 100644
--- a/bin/uuidgen/uuidgen.1
+++ b/bin/uuidgen/uuidgen.1
@@ -34,14 +34,15 @@
 .Nm
 .Op Fl 1
 .Op Fl n Ar count
+.Op Fl o Ar filename
 .Sh DESCRIPTION
 The
 .Nm
 utility by default generates a single universally unique identifier (UUID),
 also known as a globally unique identifier (GUID).
-The UUID is written to stdout.
-The following options can be used to change the number of identifiers
-and the method used:
+The UUID is written to stdout by default.
+The following options can be used to change the behaviour of
+.Nm :
 .Bl -tag -width indent
 .It Fl 1
 This option only has effect if multiple identifiers are to be generated and
@@ -52,6 +53,10 @@ to not generate them in batch, but one at a time.
 This option controls the number of identifiers generated.
 By default, multiple
 identifiers are generated in batch.
+.It Fl o
+Redirect output to
+.Ar filename 
+instead of stdout.
 .El
 .Pp
 Batched generation yields a dense set of identifiers in such a way that there
diff --git a/bin/uuidgen/uuidgen.c b/bin/uuidgen/uuidgen.c
index 0676e27..d5dac4b 100644
--- a/bin/uuidgen/uuidgen.c
+++ b/bin/uuidgen/uuidgen.c
@@ -37,20 +37,22 @@ __FBSDID("$FreeBSD$");
 static void
 usage(void)
 {
-	(void)fprintf(stderr, "usage: uuidgen [-1] [-n count]\n");
+	(void)fprintf(stderr, "usage: uuidgen [-1] [-n count] [-o filename]\n");
 	exit(1);
 }
 
 int
 main(int argc, char *argv[])
 {
+	FILE *fp;
 	uuid_t *store, *uuid;
 	char *p;
 	int ch, count, i, iterate;
 
 	count = -1;	/* no count yet */
+	fp = stdout;	/* default output file */
 	iterate = 0;	/* not one at a time */
-	while ((ch = getopt(argc, argv, "1n:")) != -1)
+	while ((ch = getopt(argc, argv, "1n:o:")) != -1)
 		switch (ch) {
 		case '1':
 			iterate = 1;
@@ -62,6 +64,13 @@ main(int argc, char *argv[])
 			if (*p != 0 || count < 1)
 				usage();
 			break;
+		case 'o':
+			if (fp != stdout)
+				errx(1, "multiple output files not allowed");
+			fp = fopen(optarg, "w");
+			if (fp == NULL)
+				err(1, "fopen");
+			break;
 		default:
 			usage();
 		}
@@ -93,10 +102,12 @@ main(int argc, char *argv[])
 	uuid = store;
 	while (count--) {
 		uuid_to_string(uuid++, &p, NULL);
-		printf("%s\n", p);
+		fprintf(fp, "%s\n", p);
 		free(p);
 	}
 
 	free(store);
+	if (fp != stdout)
+		fclose(fp);
 	return (0);
 }