diff --git a/Makefile b/Makefile
index aef4e9e3..facdf683 100644
--- a/Makefile
+++ b/Makefile
@@ -4,6 +4,10 @@ INSTALL=install
 CFLAGS+=-std=gnu99 -O2 -Wall -g -D_FILE_OFFSET_BITS=64 -I.
 LDFLAGS+=-static
 
+PKGCONFIG_LIBS="blkid uuid libnih"
+CFLAGS+=`pkg-config --cflags	${PKGCONFIG_LIBS}`
+LDLIBS+=`pkg-config --libs	${PKGCONFIG_LIBS}` -lscrypt -lsodium -lkeyutils
+
 ifeq ($(PREFIX), "/usr")
 	ROOT_SBINDIR=/sbin
 else
@@ -17,7 +21,7 @@ install: bcache
 	$(INSTALL) -m0644 -- bcache.8 $(DESTDIR)$(PREFIX)/share/man/man8/
 
 clean:
-	$(RM) -f bcache *.o *.a
+	$(RM) bcache *.o *.a
 
 CCANSRCS=$(wildcard ccan/*/*.c)
 CCANOBJS=$(patsubst %.c,%.o,$(CCANSRCS))
@@ -25,16 +29,10 @@ CCANOBJS=$(patsubst %.c,%.o,$(CCANSRCS))
 libccan.a: $(CCANOBJS)
 	$(AR) r $@ $(CCANOBJS)
 
-util.o: CFLAGS += `pkg-config --cflags blkid uuid`
-bcache.o: CFLAGS += `pkg-config --cflags libnih`
-
 bcache-objs = bcache.o bcache-assemble.o bcache-device.o bcache-format.o\
-	bcache-fs.o bcache-run.o bcache-key.o libbcache.o crypto.o
+	bcache-fs.o bcache-run.o bcache-key.o libbcache.o crypto.o util.o
 
-bcache: LDLIBS += `pkg-config --libs uuid blkid libnih` -lscrypt -lsodium -lkeyutils
-bcache: $(bcache-objs) util.o libccan.a
-
-bcache-test: LDLIBS += `pkg-config --libs openssl`
+bcache: $(bcache-objs) libccan.a
 
 deb:
 	debuild -nc -us -uc -i -I
diff --git a/bcache-assemble.c b/bcache-assemble.c
index 75669fe8..77dff3e7 100644
--- a/bcache-assemble.c
+++ b/bcache-assemble.c
@@ -8,19 +8,14 @@
 
 #include <sys/ioctl.h>
 
-#include <nih/command.h>
-#include <nih/option.h>
-
 #include "bcache.h"
-#include "bcache-assemble.h"
 
-NihOption opts_assemble[] = {
-	NIH_OPTION_LAST
-};
-
-int cmd_assemble(NihCommand *command, char *const *args)
+int cmd_assemble(int argc, char *argv[])
 {
-	unsigned nr_devs = nr_args(args);
+	unsigned nr_devs = argc - 1;
+
+	if (argc <= 1)
+		die("Please supply at least one device");
 
 	struct bch_ioctl_assemble *assemble =
 		alloca(sizeof(*assemble) + sizeof(__u64) * nr_devs);
@@ -28,8 +23,8 @@ int cmd_assemble(NihCommand *command, char *const *args)
 	memset(assemble, 0, sizeof(*assemble));
 	assemble->nr_devs = nr_devs;
 
-	for (unsigned i = 0; i < nr_devs; i++)
-	     assemble->devs[i] = (__u64) args[i];
+	for (unsigned i = 1; i < argc; i++)
+	     assemble->devs[i] = (__u64) argv[i];
 
 	int ret = ioctl(bcachectl_open(), BCH_IOCTL_ASSEMBLE, assemble);
 	if (ret < 0)
@@ -38,17 +33,13 @@ int cmd_assemble(NihCommand *command, char *const *args)
 	return 0;
 }
 
-NihOption opts_incremental[] = {
-	NIH_OPTION_LAST
-};
-
-int cmd_incremental(NihCommand *command, char *const *args)
+int cmd_incremental(int argc, char *argv[])
 {
-	if (nr_args(args) != 1)
+	if (argc != 2)
 		die("Please supply exactly one device");
 
 	struct bch_ioctl_incremental incremental = {
-		.dev = (__u64) args[0],
+		.dev = (__u64) argv[1],
 	};
 
 	int ret = ioctl(bcachectl_open(), BCH_IOCTL_INCREMENTAL, &incremental);
diff --git a/bcache-assemble.h b/bcache-assemble.h
deleted file mode 100644
index 3760478c..00000000
--- a/bcache-assemble.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#ifndef _BCACHE_ASSEMBLE_H
-#define _BCACHE_ASSEMBLE_H
-
-extern NihOption opts_assemble[];
-int cmd_assemble(NihCommand *, char * const *);
-
-extern NihOption opts_incremental[];
-int cmd_incremental(NihCommand *, char * const *);
-
-#endif /* _BCACHE_ASSEMBLE_H */
diff --git a/bcache-device.c b/bcache-device.c
index 9966d4c9..1f6f1574 100644
--- a/bcache-device.c
+++ b/bcache-device.c
@@ -13,11 +13,9 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-#include <nih/command.h>
 #include <nih/option.h>
 
 #include "bcache.h"
-#include "bcache-device.h"
 
 struct bcache_dev {
 	unsigned	nr;
@@ -82,23 +80,20 @@ static void show_dev(struct bcache_dev *dev)
 	       (dev->bytes_dirty * 100) / capacity);
 }
 
-static int human_readable;
-
-NihOption opts_device_show[] = {
-//	{ int shortoption, char *longoption, char *help, NihOptionGroup, char *argname, void *value, NihOptionSetter}
-
-	{ 'h',	"human-readable",		N_("print sizes in powers of 1024 (e.g., 1023M)"),
-		NULL, NULL,	&human_readable,	NULL},
-	NIH_OPTION_LAST
-};
-
-int cmd_device_show(NihCommand *command, char * const *args)
+int cmd_device_show(int argc, char *argv[])
 {
-	if (!args[0])
-		die("Please supply a filesystem");
+	int human_readable = 0;
+	NihOption opts[] = {
+	//	{ int shortoption, char *longoption, char *help, NihOptionGroup, char *argname, void *value, NihOptionSetter}
 
-	if (args[1])
-		die("Please supply a single filesystem");
+		{ 'h',	"human-readable",		N_("print sizes in powers of 1024 (e.g., 1023M)"),
+			NULL, NULL,	&human_readable,	NULL},
+		NIH_OPTION_LAST
+	};
+	char **args = bch_nih_init(argc, argv, opts);
+
+	if (nr_args(args) != 1)
+		die("Please supply a single device");
 
 	struct bcache_handle fs = bcache_fs_open(args[0]);
 	struct dirent *entry;
@@ -168,13 +163,14 @@ int cmd_device_show(NihCommand *command, char * const *args)
 	return 0;
 }
 
-NihOption opts_device_add[] = {
-//	{ int shortoption, char *longoption, char *help, NihOptionGroup, char *argname, void *value, NihOptionSetter}
-	NIH_OPTION_LAST
-};
-
-int cmd_device_add(NihCommand *command, char * const *args)
+int cmd_device_add(int argc, char *argv[])
 {
+	NihOption opts[] = {
+	//	{ int shortoption, char *longoption, char *help, NihOptionGroup, char *argname, void *value, NihOptionSetter}
+		NIH_OPTION_LAST
+	};
+	char **args = bch_nih_init(argc, argv, opts);
+
 	if (nr_args(args) < 2)
 		die("Please supply a filesystem and at least one device to add");
 
@@ -192,20 +188,20 @@ int cmd_device_add(NihCommand *command, char * const *args)
 	return 0;
 }
 
-static int force_data, force_metadata;
-
-NihOption opts_device_remove[] = {
-//	{ int shortoption, char *longoption, char *help, NihOptionGroup, char *argname, void *value, NihOptionSetter}
-
-	{ 'f', "force",			N_("force if data present"),
-		NULL, NULL,	&force_data, NULL },
-	{ '\0', "force-metadata",	N_("force if metadata present"),
-		NULL, NULL,	&force_metadata, NULL},
-	NIH_OPTION_LAST
-};
-
-int cmd_device_remove(NihCommand *command, char *const *args)
+int cmd_device_remove(int argc, char *argv[])
 {
+	int force_data = 0, force_metadata = 0;
+	NihOption opts[] = {
+	//	{ int shortoption, char *longoption, char *help, NihOptionGroup, char *argname, void *value, NihOptionSetter}
+
+		{ 'f', "force",			N_("force if data present"),
+			NULL, NULL,	&force_data, NULL },
+		{ '\0', "force-metadata",	N_("force if metadata present"),
+			NULL, NULL,	&force_metadata, NULL},
+		NIH_OPTION_LAST
+	};
+	char **args = bch_nih_init(argc, argv, opts);
+
 	if (nr_args(args) < 2)
 		die("Please supply a filesystem and at least one device to add");
 
diff --git a/bcache-device.h b/bcache-device.h
deleted file mode 100644
index ca9060b2..00000000
--- a/bcache-device.h
+++ /dev/null
@@ -1,14 +0,0 @@
-#ifndef _BCACHE_DEVICE_H
-#define _BCACHE_DEVICE_H
-
-extern NihOption opts_device_show[];
-int cmd_device_show(NihCommand *, char * const *);
-
-extern NihOption opts_device_add[];
-int cmd_device_add(NihCommand *, char * const *);
-
-extern NihOption opts_device_remove[];
-int cmd_device_remove(NihCommand *, char * const *);
-
-#endif /* _BCACHE_FORMAT_H */
-
diff --git a/bcache-format.c b/bcache-format.c
index e80ebed6..1b20b551 100644
--- a/bcache-format.c
+++ b/bcache-format.c
@@ -5,196 +5,238 @@
  *
  * GPLv2
  */
+#define _GNU_SOURCE
 
 #include <errno.h>
+#include <fcntl.h>
+#include <getopt.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <blkid.h>
 #include <uuid/uuid.h>
 
-#include <nih/command.h>
-#include <nih/option.h>
-
 #include "ccan/darray/darray.h"
 
 #include "bcache.h"
 #include "libbcache.h"
-#include "bcache-format.h"
 #include "crypto.h"
 
-/* All in units of 512 byte sectors */
-
-static darray(struct dev_opts) cache_devices;
-
-static unsigned block_size, btree_node_size;
-static unsigned meta_csum_type = BCH_CSUM_CRC32C;
-static unsigned data_csum_type = BCH_CSUM_CRC32C;
-static unsigned compression_type = BCH_COMPRESSION_NONE;
-static int encrypted;
-static unsigned meta_replicas = 1, data_replicas = 1;
-static unsigned on_error_action;
-static char *label = NULL;
-static uuid_le uuid;
-
-/* Device specific options: */
-static u64 filesystem_size;
-static unsigned bucket_size;
-static unsigned tier;
-static unsigned replacement_policy;
-static int discard;
-
-static int set_cache(NihOption *option, const char *arg)
+/* Open a block device, do magic blkid stuff: */
+static int open_for_format(const char *dev, bool force)
 {
-	darray_append(cache_devices, (struct dev_opts) {
-		.fd			= dev_open(arg),
-		.dev			= strdup(arg),
-		.size			= filesystem_size,
-		.bucket_size		= bucket_size,
-		.tier			= tier,
-		.replacement_policy	= replacement_policy,
-		.discard		= discard,
-	});
-	return 0;
+	blkid_probe pr;
+	const char *fs_type = NULL, *fs_label = NULL;
+	size_t fs_type_len, fs_label_len;
+	int fd;
+
+	if ((fd = open(dev, O_RDWR|O_EXCL)) == -1)
+		die("Can't open dev %s: %s\n", dev, strerror(errno));
+
+	if (force)
+		return fd;
+
+	if (!(pr = blkid_new_probe()))
+		die("blkid error 1");
+	if (blkid_probe_set_device(pr, fd, 0, 0))
+		die("blkid error 2");
+	if (blkid_probe_enable_partitions(pr, true))
+		die("blkid error 3");
+	if (blkid_do_fullprobe(pr) < 0)
+		die("blkid error 4");
+
+	blkid_probe_lookup_value(pr, "TYPE", &fs_type, &fs_type_len);
+	blkid_probe_lookup_value(pr, "LABEL", &fs_label, &fs_label_len);
+
+	if (fs_type) {
+		if (fs_label)
+			printf("%s contains a %s filesystem labelled '%s'\n",
+			       dev, fs_type, fs_label);
+		else
+			printf("%s contains a %s filesystem\n",
+			       dev, fs_type);
+		if (!ask_proceed())
+			exit(EXIT_FAILURE);
+	}
+
+	blkid_free_probe(pr);
+	return fd;
 }
 
-static int set_uuid(NihOption *option, const char *arg)
+static void usage(void)
 {
-	if (uuid_parse(arg, uuid.b))
-		die("Bad uuid");
-	return 0;
+	puts("bcache format - create a new bcache filesystem on one or more devices\n"
+	     "Usage: bcache format [OPTION]... <devices>\n"
+	     "\n"
+	     "Options:\n"
+	     "  -b, --block=size\n"
+	     "      --btree_node=size       Btree node size, default 256k\n"
+	     "      --metadata_checksum_type=(none|crc32c|crc64)\n"
+	     "      --data_checksum_type=(none|crc32c|crc64)\n"
+	     "      --compression_type=(none|lz4|gzip)\n"
+	     "      --encrypted\n"
+	     "      --error_action=(continue|readonly|panic)\n"
+	     "                              Action to take on filesystem error\n"
+	     "  -l, --label=label\n"
+	     "      --uuid=uuid\n"
+	     "  -f, --force\n"
+	     "\n"
+	     "Device specific options:\n"
+	     "      --fs_size=size          Size of filesystem on device\n"
+	     "      --bucket=size           bucket size\n"
+	     "      --discard               Enable discards\n"
+	     "  -t, --tier=#                tier of subsequent devices\n"
+	     "\n"
+	     "  -h, --help                  display this help and exit\n"
+	     "\n"
+	     "Device specific options must come before corresponding devices, e.g.\n"
+	     "  bcache format --tier 0 /dev/sdb --tier 1 /dev/sdc\n"
+	     "\n"
+	     "Report bugs to <linux-bcache@vger.kernel.org>");
+	exit(EXIT_SUCCESS);
 }
 
-static int set_block_size(NihOption *option, const char *arg)
-{
-	block_size = hatoi_validate(arg, "block size");
-	return 0;
-}
+#define OPTS								\
+	OPT('b',	block_size,		required_argument)	\
+	OPT(0,		btree_node_size,	required_argument)	\
+	OPT(0,		metadata_checksum_type,	required_argument)	\
+	OPT(0,		data_checksum_type,	required_argument)	\
+	OPT(0,		compression_type,	required_argument)	\
+	OPT(0,		encrypted,		no_argument)		\
+	OPT('e',	error_action,		required_argument)	\
+	OPT('L',	label,			required_argument)	\
+	OPT('U',	uuid,			required_argument)	\
+	OPT('f',	force,			no_argument)		\
+	OPT(0,		fs_size,		required_argument)	\
+	OPT(0,		bucket_size,		required_argument)	\
+	OPT('t',	tier,			required_argument)	\
+	OPT(0,		discard,		no_argument)		\
+	OPT('h',	help,			no_argument)
 
-static int set_bucket_sizes(NihOption *option, const char *arg)
-{
-	bucket_size = hatoi_validate(arg, "bucket size");
-	return 0;
-}
-
-static int set_btree_node_size(NihOption *option, const char *arg)
-{
-	btree_node_size = hatoi_validate(arg, "btree node size");
-	return 0;
-}
-
-static int set_filesystem_size(NihOption *option, const char *arg)
-{
-	filesystem_size = hatoi(arg) >> 9;
-	return 0;
-}
-
-static int set_replacement_policy(NihOption *option, const char *arg)
-{
-	replacement_policy = read_string_list_or_die(arg, replacement_policies,
-						     "replacement policy");
-	return 0;
-}
-
-static int set_csum_type(NihOption *option, const char *arg)
-{
-	unsigned *csum_type = option->value;
-
-	*csum_type = read_string_list_or_die(arg, csum_types, "checksum type");
-	return 0;
-}
-
-static int set_compression_type(NihOption *option, const char *arg)
-{
-	compression_type = read_string_list_or_die(arg, compression_types,
-						   "compression type");
-	return 0;
-}
-
-static int set_on_error_action(NihOption *option, const char *arg)
-{
-	on_error_action = read_string_list_or_die(arg, error_actions,
-						  "error action");
-	return 0;
-}
-
-static int set_tier(NihOption *option, const char *arg)
-{
-	tier = strtoul_or_die(arg, CACHE_TIERS, "tier");
-	return 0;
-}
-
-static int set_meta_replicas(NihOption *option, const char *arg)
-{
-	meta_replicas = strtoul_or_die(arg, CACHE_SET_META_REPLICAS_WANT_MAX,
-				       "meta_replicas");
-	return 0;
-}
-
-static int set_data_replicas(NihOption *option, const char *arg)
-{
-	data_replicas = strtoul_or_die(arg, CACHE_SET_DATA_REPLICAS_WANT_MAX,
-				       "data_replicas");
-	return 0;
-}
-
-NihOption opts_format[] = {
-//	{ int shortoption, char *longoption, char *help, NihOptionGroup, char *argname, void *value, NihOptionSetter}
-
-	{ 'C',	"cache",		N_("Format a cache device"),
-		NULL, "dev",	NULL,	set_cache },
-
-	{ 'w',	"block",		N_("block size"),
-		NULL, "size",	NULL,	set_block_size },
-	{ 'n',	"btree_node",		N_("Btree node size, default 256k"),
-		NULL, "size",	NULL,	set_btree_node_size },
-
-	{ 0,	"metadata_csum_type",	N_("Checksum type"),
-		NULL, "(none|crc32c|crc64)", &meta_csum_type, set_csum_type },
-	{ 0,	"data_csum_type",	N_("Checksum type"),
-		NULL, "(none|crc32c|crc64)", &data_csum_type, set_csum_type },
-	{ 0,	"compression_type",	N_("Compression type"),
-		NULL, "(none|gzip)", NULL, set_compression_type },
-	{ 0,	"encrypted",		N_("enable encryption"),
-		NULL, NULL,		&encrypted,	NULL },
-
-	{ 0,	"meta_replicas",	N_("number of metadata replicas"),
-		NULL, "#",	NULL,	set_meta_replicas },
-	{ 0,	"data_replicas",	N_("number of data replicas"),
-		NULL, "#",	NULL,	set_data_replicas },
-
-	{ 0,	"error_action",		N_("Action to take on filesystem error"),
-		NULL, "(continue|readonly|panic)", NULL, set_on_error_action },
-
-	{ 'l',	"label",		N_("label"),
-		NULL, "label",	&label, NULL},
-	{ 0,	"uuid",			N_("filesystem UUID"),
-		NULL, "uuid",	NULL,	set_uuid },
-
-	/* Device specific options: */
-	{ 0,	"fs_size",		N_("Size of filesystem on device" ),
-		NULL, "size",	NULL,	set_filesystem_size },
-	{ 'b',	"bucket",		N_("bucket size"),
-		NULL, "size",	NULL,	set_bucket_sizes },
-	{ 't',	"tier",			N_("tier of subsequent devices"),
-		NULL, "#",	NULL,	set_tier },
-	{ 'p',	"cache_replacement_policy", NULL,
-		NULL, "(lru|fifo|random)", NULL, set_replacement_policy },
-	{ 0,	"discard",		N_("Enable discards"),
-		NULL, NULL,		&discard,	NULL },
-
-	NIH_OPTION_LAST
+enum {
+	Opt_no_opt = 1,
+#define OPT(shortopt, longopt, has_arg)	Opt_##longopt,
+	OPTS
+#undef OPT
 };
 
-int cmd_format(NihCommand *command, char * const *args)
-{
-	char *passphrase = NULL;
+static const struct option format_opts[] = {
+#define OPT(shortopt, longopt, has_arg)	{				\
+		#longopt,  has_arg, NULL, Opt_##longopt			\
+	},
+	OPTS
+#undef OPT
+	{ NULL }
+};
 
-	if (!darray_size(cache_devices))
+int cmd_format(int argc, char *argv[])
+{
+	darray(struct dev_opts) devices;
+	struct dev_opts *dev;
+	unsigned block_size = 0;
+	unsigned btree_node_size = 0;
+	unsigned meta_csum_type = BCH_CSUM_CRC32C;
+	unsigned data_csum_type = BCH_CSUM_CRC32C;
+	unsigned compression_type = BCH_COMPRESSION_NONE;
+	bool encrypted = false;
+	unsigned on_error_action = BCH_ON_ERROR_RO;
+	char *label = NULL;
+	uuid_le uuid;
+	bool force = false;
+
+	/* Device specific options: */
+	u64 filesystem_size = 0;
+	unsigned bucket_size = 0;
+	unsigned tier = 0;
+	bool discard = false;
+	char *passphrase = NULL;
+	int opt;
+
+	darray_init(devices);
+	uuid_clear(uuid.b);
+
+	while ((opt = getopt_long(argc, argv,
+				  "-b:e:L:U:ft:h",
+				  format_opts,
+				  NULL)) != -1)
+		switch (opt) {
+		case Opt_block_size:
+		case 'b':
+			block_size = hatoi_validate(optarg,
+						"block size");
+			break;
+		case Opt_btree_node_size:
+			btree_node_size = hatoi_validate(optarg,
+						"btree node size");
+			break;
+		case Opt_metadata_checksum_type:
+			meta_csum_type = read_string_list_or_die(optarg,
+						csum_types, "checksum type");
+			break;
+		case Opt_data_checksum_type:
+			data_csum_type = read_string_list_or_die(optarg,
+						csum_types, "checksum type");
+			break;
+		case Opt_compression_type:
+			compression_type = read_string_list_or_die(optarg,
+						compression_types, "compression type");
+			break;
+		case Opt_encrypted:
+			encrypted = true;
+			break;
+		case Opt_error_action:
+		case 'e':
+			on_error_action = read_string_list_or_die(optarg,
+						error_actions, "error action");
+			break;
+		case Opt_label:
+		case 'L':
+			label = strdup(optarg);
+			break;
+		case Opt_uuid:
+		case 'U':
+			if (uuid_parse(optarg, uuid.b))
+				die("Bad uuid");
+			break;
+		case Opt_force:
+		case 'f':
+			force = true;
+			break;
+		case Opt_fs_size:
+			filesystem_size = hatoi(optarg) >> 9;
+			break;
+		case Opt_bucket_size:
+			bucket_size = hatoi_validate(optarg, "bucket size");
+			break;
+		case Opt_tier:
+		case 't':
+			tier = strtoul_or_die(optarg, CACHE_TIERS, "tier");
+			break;
+		case Opt_discard:
+			discard = true;
+			break;
+		case Opt_no_opt:
+			darray_append(devices, (struct dev_opts) {
+				.path			= strdup(optarg),
+				.size			= filesystem_size,
+				.bucket_size		= bucket_size,
+				.tier			= tier,
+				.discard		= discard,
+			});
+			break;
+		case Opt_help:
+		case 'h':
+			usage();
+			break;
+		}
+
+	if (!darray_size(devices))
 		die("Please supply a device");
 
 	if (uuid_is_null(uuid.b))
@@ -216,15 +258,18 @@ int cmd_format(NihCommand *command, char * const *args)
 		free(pass2);
 	}
 
-	bcache_format(cache_devices.item, darray_size(cache_devices),
+	darray_foreach(dev, devices)
+		dev->fd = open_for_format(dev->path, force);
+
+	bcache_format(devices.item, darray_size(devices),
 		      block_size,
 		      btree_node_size,
 		      meta_csum_type,
 		      data_csum_type,
 		      compression_type,
 		      passphrase,
-		      meta_replicas,
-		      data_replicas,
+		      1,
+		      1,
 		      on_error_action,
 		      label,
 		      uuid);
diff --git a/bcache-format.h b/bcache-format.h
deleted file mode 100644
index 0c7e72de..00000000
--- a/bcache-format.h
+++ /dev/null
@@ -1,7 +0,0 @@
-#ifndef _BCACHE_FORMAT_H
-#define _BCACHE_FORMAT_H
-
-extern NihOption opts_format[];
-int cmd_format(NihCommand *, char * const *);
-
-#endif /* _BCACHE_FORMAT_H */
diff --git a/bcache-fs.c b/bcache-fs.c
index b0438c56..f06ca378 100644
--- a/bcache-fs.c
+++ b/bcache-fs.c
@@ -1,9 +1,7 @@
 
-#include <nih/command.h>
 #include <nih/option.h>
 
 #include "bcache.h"
-#include "bcache-fs.h"
 
 struct bcache_fs {
 	/* options... */
@@ -20,13 +18,14 @@ static struct bcache_fs fill_fs(struct bcache_handle fs)
 	};
 }
 
-NihOption opts_fs_show[] = {
-//	{ int shortoption, char *longoption, char *help, NihOptionGroup, char *argname, void *value, NihOptionSetter}
-	NIH_OPTION_LAST
-};
-
-int cmd_fs_show(NihCommand *command, char *const *args)
+int cmd_fs_show(int argc, char *argv[])
 {
+	NihOption opts[] = {
+	//	{ int shortoption, char *longoption, char *help, NihOptionGroup, char *argname, void *value, NihOptionSetter}
+		NIH_OPTION_LAST
+	};
+	char **args = bch_nih_init(argc, argv, opts);
+
 	if (nr_args(args) != 1)
 		die("Please supply a filesystem");
 
@@ -35,13 +34,14 @@ int cmd_fs_show(NihCommand *command, char *const *args)
 	return 0;
 }
 
-NihOption opts_fs_set[] = {
-//	{ int shortoption, char *longoption, char *help, NihOptionGroup, char *argname, void *value, NihOptionSetter}
-	NIH_OPTION_LAST
-};
-
-int cmd_fs_set(NihCommand *command, char *const *args)
+int cmd_fs_set(int argc, char *argv[])
 {
+	NihOption opts[] = {
+	//	{ int shortoption, char *longoption, char *help, NihOptionGroup, char *argname, void *value, NihOptionSetter}
+		NIH_OPTION_LAST
+	};
+	char **args = bch_nih_init(argc, argv, opts);
+
 	if (nr_args(args) < 1)
 		die("Please supply a filesystem");
 
diff --git a/bcache-fs.h b/bcache-fs.h
deleted file mode 100644
index cd2210e9..00000000
--- a/bcache-fs.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#ifndef _BCACHE_FS_H
-#define _BCACHE_FS_H
-
-extern NihOption opts_fs_show[];
-int cmd_fs_show(NihCommand *, char * const *);
-
-extern NihOption opts_fs_set[];
-int cmd_fs_set(NihCommand *, char * const *);
-
-#endif /* _BCACHE_FS_H */
diff --git a/bcache-key.c b/bcache-key.c
index 53dbe37d..34005454 100644
--- a/bcache-key.c
+++ b/bcache-key.c
@@ -9,12 +9,13 @@
 #include "libbcache.h"
 #include "crypto.h"
 
-NihOption opts_unlock[] = {
-	NIH_OPTION_LAST
-};
-
-int cmd_unlock(NihCommand *command, char * const *args)
+int cmd_unlock(int argc, char *argv[])
 {
+	NihOption opts[] = {
+		NIH_OPTION_LAST
+	};
+	char **args = bch_nih_init(argc, argv, opts);
+
 	struct bcache_disk_key disk_key;
 	struct bcache_key key;
 	struct cache_sb sb;
@@ -38,7 +39,7 @@ int cmd_unlock(NihCommand *command, char * const *args)
 	passphrase = read_passphrase("Enter passphrase: ");
 
 	derive_passphrase(&key, passphrase);
-	disk_key_encrypt(&disk_key, &key);
+	disk_key_encrypt(&sb, &disk_key, &key);
 
 	if (memcmp(&disk_key, bch_key_header, sizeof(bch_key_header)))
 		die("incorrect passphrase");
diff --git a/bcache-key.h b/bcache-key.h
deleted file mode 100644
index 0a4df252..00000000
--- a/bcache-key.h
+++ /dev/null
@@ -1,7 +0,0 @@
-#ifndef _BCACHE_KEY_H
-#define _BCACHE_KEY_H
-
-extern NihOption opts_unlock[];
-int cmd_unlock(NihCommand *, char * const *);
-
-#endif /* _BCACHE_KEY_H */
diff --git a/bcache-run.c b/bcache-run.c
index 2f80f968..09af5837 100644
--- a/bcache-run.c
+++ b/bcache-run.c
@@ -9,29 +9,29 @@
 #include <sys/ioctl.h>
 #include <unistd.h>
 
-#include <nih/command.h>
 #include <nih/option.h>
 
 #include <uuid/uuid.h>
 
 #include "bcache.h"
-#include "bcache-run.h"
 
-NihOption opts_run[] = {
-	NIH_OPTION_LAST
-};
-
-int cmd_run(NihCommand *command, char *const *args)
+int cmd_run(int argc, char *argv[])
 {
+	NihOption opts[] = {
+		NIH_OPTION_LAST
+	};
+	bch_nih_init(argc, argv, opts);
+
 	return 0;
 }
 
-NihOption opts_stop[] = {
-	NIH_OPTION_LAST
-};
-
-int cmd_stop(NihCommand *command, char *const *args)
+int cmd_stop(int argc, char *argv[])
 {
+	NihOption opts[] = {
+		NIH_OPTION_LAST
+	};
+	char **args = bch_nih_init(argc, argv, opts);
+
 	if (nr_args(args) != 1)
 		die("Please supply a filesystem");
 
diff --git a/bcache-run.h b/bcache-run.h
deleted file mode 100644
index 66ea892f..00000000
--- a/bcache-run.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#ifndef _BCACHE_RUN_H
-#define _BCACHE_RUN_H
-
-extern NihOption opts_run[];
-int cmd_run(NihCommand *, char * const *);
-
-extern NihOption opts_stop[];
-int cmd_stop(NihCommand *, char * const *);
-
-#endif /* _BCACHE_RUN_H */
diff --git a/bcache.c b/bcache.c
index bf975ae8..532194d1 100644
--- a/bcache.c
+++ b/bcache.c
@@ -6,10 +6,6 @@
  * GPLv2
  */
 
-#include <nih/option.h>
-#include <nih/command.h>
-#include <nih/main.h>
-#include <nih/logging.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <ctype.h>
@@ -26,16 +22,6 @@
 #include <sys/stat.h>
 
 #include "bcache.h"
-#include "bcache-assemble.h"
-#include "bcache-device.h"
-#include "bcache-format.h"
-#include "bcache-fs.h"
-#include "bcache-run.h"
-#include "bcache-key.h"
-
-#define PACKAGE_NAME "bcache"
-#define PACKAGE_VERSION "1.0"
-#define PACKAGE_BUGREPORT "linux-bcache@vger.kernel.org"
 
 const char * const cache_state[] = {
 	"active",
@@ -89,82 +75,70 @@ const char * const bdev_state[] = {
 	NULL
 };
 
-#define CMD(_command, _usage, _synopsis)				\
-{									\
-	.command	= #_command,					\
-	.usage		= _usage,					\
-	.synopsis	= _synopsis,					\
-	.help		= NULL,						\
-	.group		= NULL,						\
-	.options	= opts_##_command,				\
-	.action		= cmd_##_command,				\
+static void usage(void)
+{
+	puts("bcache - tool for managing bcache volumes/filesystems\n"
+	     "usage: bcache <command> [<args>]\n"
+	     "\n"
+	     "Commands for formatting, startup and shutdown\n"
+	     "  format         Format a new filesystem\n"
+	     "  unlock         Unlock an encrypted filesystem prior to running/mounting\n"
+	     "  assemble       Assemble an existing multi device filesystem\n"
+	     "  incremental    Incrementally assemble an existing multi device filesystem\n"
+	     "  run            Start a partially assembled filesystem\n"
+	     "  stop	       Stop a running filesystem\n"
+	     "\n"
+	     "Commands for managing a running filesystem\n"
+	     "  fs_show        Show various information about a filesystem\n"
+	     "  fs_set         Modify filesystem options\n"
+	     "\n"
+	     "Commands for managing a specific device in a filesystem\n"
+	     "  device_show    Show information about a formatted device\n"
+	     "  device_add     Add a device to an existing (running) filesystem\n"
+	     "  device_remove  Remove a device from an existing (running) filesystem\n");
+	exit(EXIT_SUCCESS);
 }
 
-static NihCommand commands[] = {
-	CMD(format, N_("<list of devices>"),
-	    "Create a new bcache volume from one or more devices"),
-
-	/* Bringup, shutdown */
-
-	CMD(assemble, N_("<devices>"),
-	    "Assembles one or more devices into a bcache volume"),
-	CMD(incremental, N_("<device"),
-	    "Incrementally assemble a bcache filesystem"),
-	CMD(run, N_("<volume>"),
-	    "Start a partially assembled volume"),
-	CMD(stop, N_("<volume>"),
-	    "Stops a running bcache volume"),
-
-	/* Filesystem commands: */
-
-	CMD(fs_show, N_("<fs>"),
-	    "Show information about a filesystem"),
-	CMD(fs_set, N_("<fs>"),
-	    "Change various filesystem options"),
-
-	/* Device commands: */
-
-	CMD(device_show, N_("<fs>"),
-	    "Show information about component devices of a filesystem"),
-	CMD(device_add, N_("<volume> <devices>"),
-	    "Adds a list of devices to a volume"),
-	CMD(device_remove, N_("<volume> <devices>"),
-	    "Removes a device from its volume"),
-
-	/* Crypto */
-
-	CMD(unlock, N_("<device>"),
-	    "Unlock an encrypted filesystem"),
-
-#if 0
-	CMD(modify, N_("<options>"),
-	    "Modifies attributes related to the volume",
-	    N_("Modifies attributes related to the volume")),
-	CMD(list, N_("list-cachesets"),
-	    "Lists cachesets in /sys/fs/bcache"),
-	CMD(query, N_("query <list of devices>"),
-	    "Gives info about the superblock of a list of devices"),
-	CMD(status, N_("status <list of devices>"),
-	    "Finds the status of the most up to date superblock"),
-#endif
-	NIH_COMMAND_LAST
-};
-
-static NihOption options[] = {
-	NIH_OPTION_LAST
-};
-
 int main(int argc, char *argv[])
 {
-	nih_main_init(argv[0]);
-	nih_option_set_synopsis(_("Manage bcache devices"));
-	nih_option_set_help( _("Helps you manage bcache devices"));
+	char *cmd;
 
-	int ret = nih_command_parser(NULL, argc, argv, options, commands);
-	if (ret < 0)
+	if (argc < 2) {
+		printf("%s: missing command\n", argv[0]);
 		exit(EXIT_FAILURE);
+	}
 
-	nih_signal_reset();
+	cmd = argv[1];
 
+	memmove(&argv[1], &argv[2], argc * sizeof(argv[0]));
+	argc--;
+
+	if (!strcmp(cmd, "format"))
+		return cmd_format(argc, argv);
+	if (!strcmp(cmd, "assemble"))
+		return cmd_assemble(argc, argv);
+	if (!strcmp(cmd, "incremental"))
+		return cmd_incremental(argc, argv);
+	if (!strcmp(cmd, "run"))
+		return cmd_run(argc, argv);
+	if (!strcmp(cmd, "stop"))
+		return cmd_stop(argc, argv);
+
+	if (!strcmp(cmd, "fs_show"))
+		return cmd_fs_show(argc, argv);
+	if (!strcmp(cmd, "fs_set"))
+		return cmd_fs_set(argc, argv);
+
+	if (!strcmp(cmd, "device_show"))
+		return cmd_device_show(argc, argv);
+	if (!strcmp(cmd, "device_add"))
+		return cmd_device_add(argc, argv);
+	if (!strcmp(cmd, "device_remove"))
+		return cmd_device_remove(argc, argv);
+
+	if (!strcmp(cmd, "unlock"))
+		return cmd_unlock(argc, argv);
+
+	usage();
 	return 0;
 }
diff --git a/bcache.h b/bcache.h
index a3ff1b3c..69d3edc3 100644
--- a/bcache.h
+++ b/bcache.h
@@ -17,4 +17,19 @@ extern const char * const error_actions[];
 extern const char * const bdev_cache_mode[];
 extern const char * const bdev_state[];
 
+int cmd_format(int argc, char *argv[]);
+
+int cmd_unlock(int argc, char *argv[]);
+int cmd_assemble(int argc, char *argv[]);
+int cmd_incremental(int argc, char *argv[]);
+int cmd_run(int argc, char *argv[]);
+int cmd_stop(int argc, char *argv[]);
+
+int cmd_fs_show(int argc, char *argv[]);
+int cmd_fs_set(int argc, char *argv[]);
+
+int cmd_device_show(int argc, char *argv[]);
+int cmd_device_add(int argc, char *argv[]);
+int cmd_device_remove(int argc, char *argv[]);
+
 #endif /* _BCACHE_H */
diff --git a/crypto.c b/crypto.c
index 5bf569de..e98e4867 100644
--- a/crypto.c
+++ b/crypto.c
@@ -21,7 +21,6 @@ char *read_passphrase(const char *prompt)
 	struct termios old, new;
 	char *buf = NULL;
 	size_t buflen = 0;
-	ssize_t ret;
 
 	fprintf(stderr, "%s", prompt);
 	fflush(stderr);
@@ -34,8 +33,7 @@ char *read_passphrase(const char *prompt)
 	if (tcsetattr(fileno(stdin), TCSAFLUSH, &new))
 		die("error setting terminal attrs");
 
-	ret = getline(&buf, &buflen, stdin);
-	if (ret <= 0)
+	if (getline(&buf, &buflen, stdin) <= 0)
 		die("error reading passphrase");
 
 	tcsetattr(fileno(stdin), TCSAFLUSH, &old);
diff --git a/libbcache.c b/libbcache.c
index 81d70d1b..b565fa8c 100644
--- a/libbcache.c
+++ b/libbcache.c
@@ -59,12 +59,12 @@ void bcache_format(struct dev_opts *devs, size_t nr_devs,
 	if (!block_size)
 		for (i = devs; i < devs + nr_devs; i++)
 			block_size = max(block_size,
-					 get_blocksize(i->dev, i->fd));
+					 get_blocksize(i->path, i->fd));
 
 	/* calculate bucket sizes: */
 	for (i = devs; i < devs + nr_devs; i++) {
 		if (!i->size)
-			i->size = get_size(i->dev, i->fd);
+			i->size = get_size(i->path, i->fd);
 
 		if (!i->bucket_size) {
 			u64 bytes = i->size << 9;
@@ -125,8 +125,7 @@ void bcache_format(struct dev_opts *devs, size_t nr_devs,
 	SET_CACHE_SET_DATA_REPLICAS_WANT(sb,	data_replicas);
 	SET_CACHE_SET_DATA_REPLICAS_HAVE(sb,	data_replicas);
 	SET_CACHE_SET_ERROR_ACTION(sb,		on_error_action);
-
-	SET_CACHE_SET_STR_HASH_TYPE(sb, BCH_STR_HASH_SIPHASH);
+	SET_CACHE_SET_STR_HASH_TYPE(sb,		BCH_STR_HASH_SIPHASH);
 
 	if (passphrase) {
 		struct bcache_key key;
@@ -153,7 +152,7 @@ void bcache_format(struct dev_opts *devs, size_t nr_devs,
 		m->bucket_size	= __cpu_to_le16(i->bucket_size);
 
 		SET_CACHE_TIER(m,		i->tier);
-		SET_CACHE_REPLACEMENT(m,	i->replacement_policy);
+		SET_CACHE_REPLACEMENT(m,	CACHE_REPLACEMENT_LRU);
 		SET_CACHE_DISCARD(m,		i->discard);
 	}
 
diff --git a/libbcache.h b/libbcache.h
index c8d668ec..ccfa37cb 100644
--- a/libbcache.h
+++ b/libbcache.h
@@ -6,11 +6,10 @@
 
 struct dev_opts {
 	int		fd;
-	const char	*dev;
+	const char	*path;
 	u64		size; /* 512 byte sectors */
 	unsigned	bucket_size;
 	unsigned	tier;
-	unsigned	replacement_policy;
 	bool		discard;
 
 	u64		first_bucket;
diff --git a/util.c b/util.c
index 8369d6be..bd332b5b 100644
--- a/util.c
+++ b/util.c
@@ -12,7 +12,6 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-#include <blkid.h>
 #include <uuid/uuid.h>
 
 #include "ccan/crc/crc.h"
@@ -248,32 +247,6 @@ unsigned get_blocksize(const char *path, int fd)
 	return ret >> 9;
 }
 
-/* Open a block device, do magic blkid stuff: */
-int dev_open(const char *dev)
-{
-	blkid_probe pr;
-	int fd;
-
-	if ((fd = open(dev, O_RDWR|O_EXCL)) == -1)
-		die("Can't open dev %s: %s\n", dev, strerror(errno));
-
-	if (!(pr = blkid_new_probe()))
-		die("Failed to create a new probe");
-	if (blkid_probe_set_device(pr, fd, 0, 0))
-		die("failed to set probe to device");
-
-	/* enable ptable probing; superblock probing is enabled by default */
-	if (blkid_probe_enable_partitions(pr, true))
-		die("Failed to enable partitions on probe");
-
-	if (!blkid_do_probe(pr))
-		/* XXX wipefs doesn't know how to remove partition tables */
-		die("Device %s already has a non-bcache superblock, "
-		    "remove it using wipefs and wipefs -a\n", dev);
-
-	return fd;
-}
-
 /* Checksums: */
 
 /*
@@ -488,8 +461,43 @@ struct bcache_handle bcache_fs_open(const char *path)
 	return ret;
 }
 
+bool ask_proceed(void)
+{
+	const char *short_yes = "yY";
+	char *buf = NULL;
+	size_t buflen = 0;
+	bool ret;
+
+	fputs("Proceed anyway? (y,n) ", stdout);
+
+	if (getline(&buf, &buflen, stdin) < 0)
+		die("error reading from standard input");
+
+	ret = strchr(short_yes, buf[0]);
+	free(buf);
+	return ret;
+}
+
 void memzero_explicit(void *buf, size_t len)
 {
     void *(* volatile memset_s)(void *s, int c, size_t n) = memset;
     memset_s(buf, 0, len);
 }
+
+/* libnih options: */
+
+#include <nih/option.h>
+#include <nih/main.h>
+
+#define PACKAGE_NAME "bcache"
+#define PACKAGE_VERSION "1.0"
+#define PACKAGE_BUGREPORT "linux-bcache@vger.kernel.org"
+
+char **bch_nih_init(int argc, char *argv[], NihOption *options)
+{
+	nih_main_init(argv[0]);
+	nih_option_set_synopsis(_("Manage bcache devices"));
+	nih_option_set_help( _("Helps you manage bcache devices"));
+
+	return nih_option_parser(NULL, argc, argv, options, 0);
+}
diff --git a/util.h b/util.h
index 101b5c86..34afccbc 100644
--- a/util.h
+++ b/util.h
@@ -1,6 +1,7 @@
 #ifndef _UTIL_H
 #define _UTIL_H
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/types.h>
@@ -59,8 +60,6 @@ void print_string_list(const char * const[], size_t);
 u64 get_size(const char *, int);
 unsigned get_blocksize(const char *, int);
 
-int dev_open(const char *);
-
 #include "bcache-ondisk.h"
 #include "bcache-ioctl.h"
 
@@ -93,6 +92,11 @@ struct bcache_handle {
 
 struct bcache_handle bcache_fs_open(const char *);
 
+bool ask_proceed(void);
+
 void memzero_explicit(void *, size_t);
 
+struct nih_option;
+char **bch_nih_init(int argc, char *argv[], struct nih_option *options);
+
 #endif /* _UTIL_H */