The --include='pattern' option is the natural counterpart to

--exclude='pattern'.

I should have added this a long time ago, since it's so useful for testing.
In particular, it allows me to select a few entries from a troublesome
archive so that I can easily focus my debugging efforts:
   bsdtar -czf new.tgz --include='*foo*' @old.tgz

2 files changed, 25 insertions, 0 deletions

diff --git a/usr.bin/tar/bsdtar.1 b/usr.bin/tar/bsdtar.1
index 994d639..4d36d09 100644
--- a/usr.bin/tar/bsdtar.1
+++ b/usr.bin/tar/bsdtar.1
@@ -195,6 +195,24 @@ target of the link will be archived, not the link itself.
 (c and r mode only)
 Synonym for
 .Fl L .
+.It Fl -include Ar pattern
+Process only files or directories that match the specified pattern.
+Note that exclusions specified with
+.Fl -exclude
+take precedence over inclusions.
+If no inclusions are explicitly specified, all entries are processed by
+default.
+The
+.Fl -include
+option is especially useful when filtering archives.
+For example, the command
+.Dl Nm Fl c Fl f Pa new.tar Fl -include='*foo*' Cm @ Ns Pa old.tgz
+creates a new archive
+.Pa new.tar
+containing only the entries from
+.Pa old.tgz
+containing the string
+.Sq foo .
 .It Fl j
 (c mode only)
 Compress the resulting archive with
diff --git a/usr.bin/tar/bsdtar.c b/usr.bin/tar/bsdtar.c
index ccf7c28..7092fc0 100644
--- a/usr.bin/tar/bsdtar.c
+++ b/usr.bin/tar/bsdtar.c
@@ -74,6 +74,7 @@ const char *tar_opts = "Bb:C:cF:f:HhjkLlmnOoPprtT:UuvwXxyZz";
 #define	OPTION_FAST_READ 2
 #define	OPTION_NODUMP 3
 #define	OPTION_HELP 4
+#define	OPTION_INCLUDE 5
 
 const struct option tar_longopts[] = {
 	{ "absolute-paths",     no_argument,       NULL, 'P' },
@@ -95,6 +96,7 @@ const struct option tar_longopts[] = {
 	{ "gunzip",             no_argument,       NULL, 'z' },
 	{ "gzip",               no_argument,       NULL, 'z' },
 	{ "help",               no_argument,       NULL, OPTION_HELP },
+	{ "include",            required_argument, NULL, OPTION_INCLUDE },
 	{ "interactive",        no_argument,       NULL, 'w' },
 	{ "keep-old-files",     no_argument,       NULL, 'k' },
 	{ "list",               no_argument,       NULL, 't' },
@@ -228,6 +230,11 @@ main(int argc, char **argv)
 			long_help(bsdtar);
 			break;
 #endif
+#ifdef HAVE_GETOPT_LONG
+		case OPTION_INCLUDE:
+			include(bsdtar, optarg);
+			break;
+#endif
 		case 'j': /* GNU tar */
 			if (bsdtar->create_compression != '\0')
 				bsdtar_errc(bsdtar, 1, 0,