diff --git a/builtin/replace.c b/builtin/replace.c
@@ -54,7 +54,7 @@ static int show_reference(const char *refname, const struct object_id *oid,
 			enum object_type obj_type, repl_type;
 
 			if (get_oid(refname, &object))
-				return error("Failed to resolve '%s' as a valid ref.", refname);
+				return error("failed to resolve '%s' as a valid ref", refname);
 
 			obj_type = oid_object_info(the_repository, &object,
 						   NULL);
@@ -84,7 +84,7 @@ static int list_replace_refs(const char *pattern, const char *format)
 		data.format = REPLACE_FORMAT_LONG;
 	else
 		return error("invalid replace format '%s'\n"
-			     "valid formats are 'short', 'medium' and 'long'\n",
+			     "valid formats are 'short', 'medium' and 'long'",
 			     format);
 
 	for_each_replace_ref(the_repository, show_reference, (void *)&data);
@@ -108,7 +108,7 @@ static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
 
 	for (p = argv; *p; p++) {
 		if (get_oid(*p, &oid)) {
-			error("Failed to resolve '%s' as a valid ref.", *p);
+			error("failed to resolve '%s' as a valid ref", *p);
 			had_error = 1;
 			continue;
 		}
@@ -118,7 +118,7 @@ static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
 		full_hex = ref.buf + base_len;
 
 		if (read_ref(ref.buf, &oid)) {
-			error("replace ref '%s' not found.", full_hex);
+			error("replace ref '%s' not found", full_hex);
 			had_error = 1;
 			continue;
 		}
@@ -134,7 +134,7 @@ static int delete_replace_ref(const char *name, const char *ref,
 {
 	if (delete_ref(NULL, ref, oid, 0))
 		return 1;
-	printf("Deleted replace ref '%s'\n", name);
+	printf_ln("Deleted replace ref '%s'", name);
 	return 0;
 }
 
@@ -146,7 +146,7 @@ static int check_ref_valid(struct object_id *object,
 	strbuf_reset(ref);
 	strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
 	if (check_refname_format(ref->buf, 0))
-		return error("'%s' is not a valid ref name.", ref->buf);
+		return error("'%s' is not a valid ref name", ref->buf);
 
 	if (read_ref(ref->buf, prev))
 		oidclr(prev);
@@ -200,10 +200,10 @@ static int replace_object(const char *object_ref, const char *replace_ref, int f
 	struct object_id object, repl;
 
 	if (get_oid(object_ref, &object))
-		return error("Failed to resolve '%s' as a valid ref.",
+		return error("failed to resolve '%s' as a valid ref",
 			     object_ref);
 	if (get_oid(replace_ref, &repl))
-		return error("Failed to resolve '%s' as a valid ref.",
+		return error("failed to resolve '%s' as a valid ref",
 			     replace_ref);
 
 	return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
@@ -315,7 +315,7 @@ static int edit_and_replace(const char *object_ref, int force, int raw)
 	struct strbuf ref = STRBUF_INIT;
 
 	if (get_oid(object_ref, &old_oid) < 0)
-		return error("Not a valid object name: '%s'", object_ref);
+		return error("not a valid object name: '%s'", object_ref);
 
 	type = oid_object_info(the_repository, &old_oid, NULL);
 	if (type < 0)
@@ -368,7 +368,7 @@ static int replace_parents(struct strbuf *buf, int argc, const char **argv)
 		struct object_id oid;
 		if (get_oid(argv[i], &oid) < 0) {
 			strbuf_release(&new_parents);
-			return error(_("Not a valid object name: '%s'"),
+			return error(_("not a valid object name: '%s'"),
 				     argv[i]);
 		}
 		if (!lookup_commit_reference(&oid)) {
@@ -412,7 +412,7 @@ static int check_one_mergetag(struct commit *commit,
 	for (i = 1; i < mergetag_data->argc; i++) {
 		struct object_id oid;
 		if (get_oid(mergetag_data->argv[i], &oid) < 0)
-			return error(_("Not a valid object name: '%s'"),
+			return error(_("not a valid object name: '%s'"),
 				     mergetag_data->argv[i]);
 		if (!oidcmp(&tag->tagged->oid, &oid))
 			return 0; /* found */
@@ -442,7 +442,7 @@ static int create_graft(int argc, const char **argv, int force, int gentle)
 	unsigned long size;
 
 	if (get_oid(old_ref, &old_oid) < 0)
-		return error(_("Not a valid object name: '%s'"), old_ref);
+		return error(_("not a valid object name: '%s'"), old_ref);
 	commit = lookup_commit_reference(&old_oid);
 	if (!commit)
 		return error(_("could not parse %s"), old_ref);
@@ -457,7 +457,7 @@ static int create_graft(int argc, const char **argv, int force, int gentle)
 	}
 
 	if (remove_signature(&buf)) {
-		warning(_("the original commit '%s' has a gpg signature."), old_ref);
+		warning(_("the original commit '%s' has a gpg signature"), old_ref);
 		warning(_("the signature will be removed in the replacement commit!"));
 	}
 

diff --git a/builtin/rm.c b/builtin/rm.c
@@ -285,7 +285,7 @@ int cmd_rm(int argc, const char **argv, const char *prefix)
 		list.entry[list.nr].is_submodule = S_ISGITLINK(ce->ce_mode);
 		if (list.entry[list.nr++].is_submodule &&
 		    !is_staging_gitmodules_ok(&the_index))
-			die (_("Please stage your changes to .gitmodules or stash them to proceed"));
+			die(_("please stage your changes to .gitmodules or stash them to proceed"));
 	}
 
 	if (pathspec.nr) {

diff --git a/config.c b/config.c
@@ -461,7 +461,7 @@ int git_config_from_parameters(config_fn_t fn, void *data)
 	envw = xstrdup(env);
 
 	if (sq_dequote_to_argv(envw, &argv, &nr, &alloc) < 0) {
-		ret = error("bogus format in " CONFIG_DATA_ENVIRONMENT);
+		ret = error("bogus format in %s", CONFIG_DATA_ENVIRONMENT);
 		goto out;
 	}
 
@@ -1411,8 +1411,8 @@ static int git_default_push_config(const char *var, const char *value)
 			push_default = PUSH_DEFAULT_CURRENT;
 		else {
 			error("malformed value for %s: %s", var, value);
-			return error("Must be one of nothing, matching, simple, "
-				     "upstream or current.");
+			return error("must be one of nothing, matching, simple, "
+				     "upstream or current");
 		}
 		return 0;
 	}

diff --git a/connect.c b/connect.c
@@ -58,7 +58,7 @@ static NORETURN void die_initial_contact(int unexpected)
 	 * response does not necessarily mean an ACL problem, though.
 	 */
 	if (unexpected)
-		die(_("The remote end hung up upon initial contact"));
+		die(_("the remote end hung up upon initial contact"));
 	else
 		die(_("Could not read from remote repository.\n\n"
 		      "Please make sure you have the correct access rights\n"
@@ -230,7 +230,7 @@ static int process_dummy_ref(const char *line)
 static void check_no_capabilities(const char *line, int len)
 {
 	if (strlen(line) != len)
-		warning("Ignoring capabilities after first line '%s'",
+		warning("ignoring capabilities after first line '%s'",
 			line + strlen(line));
 }
 
@@ -544,7 +544,7 @@ static enum protocol get_protocol(const char *name)
 		return PROTO_SSH;
 	if (!strcmp(name, "file"))
 		return PROTO_FILE;
-	die("I don't handle protocol '%s'", name);
+	die("protocol '%s' is not supported", name);
 }
 
 static char *host_end(char **hoststart, int removebrackets)
@@ -595,8 +595,7 @@ static void enable_keepalive(int sockfd)
 	int ka = 1;
 
 	if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
-		fprintf(stderr, "unable to set SO_KEEPALIVE on socket: %s\n",
-			strerror(errno));
+		error_errno("unable to set SO_KEEPALIVE on socket");
 }
 
 #ifndef NO_IPV6
@@ -640,7 +639,7 @@ static int git_tcp_connect_sock(char *host, int flags)
 
 	gai = getaddrinfo(host, port, &hints, &ai);
 	if (gai)
-		die("Unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
+		die("unable to look up %s (port %s) (%s)", host, port, gai_strerror(gai));
 
 	if (flags & CONNECT_VERBOSE)
 		fprintf(stderr, "done.\nConnecting to %s (port %s) ... ", host, port);
@@ -670,7 +669,7 @@ static int git_tcp_connect_sock(char *host, int flags)
 	enable_keepalive(sockfd);
 
 	if (flags & CONNECT_VERBOSE)
-		fprintf(stderr, "done.\n");
+		fprintf_ln(stderr, "done.");
 
 	strbuf_release(&error_message);
 
@@ -701,13 +700,13 @@ static int git_tcp_connect_sock(char *host, int flags)
 
 	he = gethostbyname(host);
 	if (!he)
-		die("Unable to look up %s (%s)", host, hstrerror(h_errno));
+		die("unable to look up %s (%s)", host, hstrerror(h_errno));
 	nport = strtoul(port, &ep, 10);
 	if ( ep == port || *ep ) {
 		/* Not numeric */
 		struct servent *se = getservbyname(port,"tcp");
 		if ( !se )
-			die("Unknown port %s", port);
+			die("unknown port %s", port);
 		nport = se->s_port;
 	}
 
@@ -745,7 +744,7 @@ static int git_tcp_connect_sock(char *host, int flags)
 	enable_keepalive(sockfd);
 
 	if (flags & CONNECT_VERBOSE)
-		fprintf(stderr, "done.\n");
+		fprintf_ln(stderr, "done.");
 
 	return sockfd;
 }
@@ -921,7 +920,7 @@ static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 		path = strchr(end, separator);
 
 	if (!path || !*path)
-		die("No path specified. See 'man git-pull' for valid url syntax");
+		die("no path specified; see 'git help pull' for valid url syntax");
 
 	/*
 	 * null-terminate hostname and point path to ~ for URL's like this:

diff --git a/convert.c b/convert.c
@@ -190,7 +190,7 @@ static enum eol output_eol(enum crlf_action crlf_action)
 		/* fall through */
 		return text_eol_is_crlf() ? EOL_CRLF : EOL_LF;
 	}
-	warning("Illegal crlf_action %d\n", (int)crlf_action);
+	warning("illegal crlf_action %d", (int)crlf_action);
 	return core_eol;
 }
 
@@ -203,7 +203,7 @@ static void check_global_conv_flags_eol(const char *path, enum crlf_action crlf_
 		 * CRLFs would not be restored by checkout
 		 */
 		if (conv_flags & CONV_EOL_RNDTRP_DIE)
-			die(_("CRLF would be replaced by LF in %s."), path);
+			die(_("CRLF would be replaced by LF in %s"), path);
 		else if (conv_flags & CONV_EOL_RNDTRP_WARN)
 			warning(_("CRLF will be replaced by LF in %s.\n"
 				  "The file will have its original line"
@@ -493,7 +493,7 @@ static int encode_to_worktree(const char *path, const char *src, size_t src_len,
 				  &dst_len);
 	if (!dst) {
 		error("failed to encode '%s' from %s to %s",
-			path, default_encoding, enc);
+		      path, default_encoding, enc);
 		return 0;
 	}
 

diff --git a/diff.c b/diff.c
@@ -1863,8 +1863,8 @@ static void init_diff_words_data(struct emit_callback *ecbdata,
 		if (regcomp(ecbdata->diff_words->word_regex,
 			    o->word_regex,
 			    REG_EXTENDED | REG_NEWLINE))
-			die ("Invalid regular expression: %s",
-			     o->word_regex);
+			die("invalid regular expression: %s",
+			    o->word_regex);
 	}
 	for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
 		if (o->word_diff == diff_words_styles[i].type) {

diff --git a/dir.c b/dir.c
@@ -560,7 +560,7 @@ int report_path_error(const char *ps_matched,
 		if (found_dup)
 			continue;
 
-		error("pathspec '%s' did not match any file(s) known to git.",
+		error("pathspec '%s' did not match any file(s) known to git",
 		      pathspec->items[num].original);
 		errors++;
 	}
@@ -2230,7 +2230,7 @@ static struct untracked_cache_dir *validate_untracked_cache(struct dir_struct *d
 		return NULL;
 
 	if (!ident_in_untracked(dir->untracked)) {
-		warning(_("Untracked cache is disabled on this system or location."));
+		warning(_("untracked cache is disabled on this system or location"));
 		return NULL;
 	}
 

diff --git a/pkt-line.c b/pkt-line.c
@@ -296,7 +296,7 @@ static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 		if (options & PACKET_READ_GENTLE_ON_EOF)
 			return -1;
 
-		die("The remote end hung up unexpectedly");
+		die("the remote end hung up unexpectedly");
 	}
 
 	return ret;

diff --git a/reflog-walk.c b/reflog-walk.c
@@ -128,7 +128,7 @@ int add_reflog_for_walk(struct reflog_walk_info *info,
 	enum selector_type selector = SELECTOR_NONE;
 
 	if (commit->object.flags & UNINTERESTING)
-		die ("Cannot walk reflogs for %s", name);
+		die("cannot walk reflogs for %s", name);
 
 	branch = xstrdup(name);
 	if (at && at[1] == '{') {
@@ -153,7 +153,7 @@ int add_reflog_for_walk(struct reflog_walk_info *info,
 			free(branch);
 			branch = resolve_refdup("HEAD", 0, NULL, NULL);
 			if (!branch)
-				die ("No current branch");
+				die("no current branch");
 
 		}
 		reflogs = read_complete_reflog(branch);

diff --git a/refs.c b/refs.c
@@ -567,9 +567,9 @@ int expand_ref(const char *str, int len, struct object_id *oid, char **ref)
 			if (!warn_ambiguous_refs)
 				break;
 		} else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
-			warning("ignoring dangling symref %s.", fullref.buf);
+			warning("ignoring dangling symref %s", fullref.buf);
 		} else if ((flag & REF_ISBROKEN) && strchr(fullref.buf, '/')) {
-			warning("ignoring broken ref %s.", fullref.buf);
+			warning("ignoring broken ref %s", fullref.buf);
 		}
 	}
 	strbuf_release(&fullref);
@@ -871,13 +871,13 @@ static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
 		if (!is_null_oid(&cb->ooid)) {
 			oidcpy(cb->oid, noid);
 			if (oidcmp(&cb->ooid, noid))
-				warning("Log for ref %s has gap after %s.",
+				warning("log for ref %s has gap after %s",
 					cb->refname, show_date(cb->date, cb->tz, DATE_MODE(RFC2822)));
 		}
 		else if (cb->date == cb->at_time)
 			oidcpy(cb->oid, noid);
 		else if (oidcmp(noid, cb->oid))
-			warning("Log for ref %s unexpectedly ended on %s.",
+			warning("log for ref %s unexpectedly ended on %s",
 				cb->refname, show_date(cb->date, cb->tz,
 						       DATE_MODE(RFC2822)));
 		oidcpy(&cb->ooid, ooid);
@@ -935,7 +935,7 @@ int read_ref_at(const char *refname, unsigned int flags, timestamp_t at_time, in
 		if (flags & GET_OID_QUIETLY)
 			exit(128);
 		else
-			die("Log for %s is empty.", refname);
+			die("log for %s is empty", refname);
 	}
 	if (cb.found_it)
 		return 0;
@@ -1845,7 +1845,7 @@ int ref_update_reject_duplicates(struct string_list *refnames,
 
 		if (!cmp) {
 			strbuf_addf(err,
-				    "multiple updates for ref '%s' not allowed.",
+				    "multiple updates for ref '%s' not allowed",
 				    refnames->items[i].string);
 			return 1;
 		} else if (cmp > 0) {

diff --git a/refspec.c b/refspec.c
@@ -134,7 +134,7 @@ void refspec_item_init_or_die(struct refspec_item *item, const char *refspec,
 			      int fetch)
 {
 	if (!refspec_item_init(item, refspec, fetch))
-		die("Invalid refspec '%s'", refspec);
+		die("invalid refspec '%s'", refspec);
 }
 
 void refspec_item_clear(struct refspec_item *item)

diff --git a/sequencer.c b/sequencer.c
@@ -306,7 +306,7 @@ static const char *action_name(const struct replay_opts *opts)
 	case REPLAY_INTERACTIVE_REBASE:
 		return N_("rebase -i");
 	}
-	die(_("Unknown action: %d"), opts->action);
+	die(_("unknown action: %d"), opts->action);
 }
 
 struct commit_message {
@@ -1444,7 +1444,7 @@ static const char *command_to_string(const enum todo_command command)
 {
 	if (command < TODO_COMMENT)
 		return todo_command_info[command].str;
-	die("Unknown command: %d", command);
+	die("unknown command: %d", command);
 }
 
 static char command_to_char(const enum todo_command command)
@@ -2608,7 +2608,7 @@ static int error_with_patch(struct commit *commit,
 			"\n"
 			"  git rebase --continue\n", gpg_sign_opt_quoted(opts));
 	} else if (exit_code)
-		fprintf(stderr, "Could not apply %s... %.*s\n",
+		fprintf_ln(stderr, "Could not apply %s... %.*s",
 			short_commit_name(commit), subject_len, subject);
 
 	return exit_code;
@@ -2719,7 +2719,7 @@ static int do_label(const char *name, int len)
 	struct object_id head_oid;
 
 	if (len == 1 && *name == '#')
-		return error("Illegal label name: '%.*s'", len, name);
+		return error("illegal label name: '%.*s'", len, name);
 
 	strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
 	strbuf_addf(&msg, "rebase -i (label) '%.*s'", len, name);

diff --git a/sha1-file.c b/sha1-file.c
@@ -71,17 +71,17 @@ static void git_hash_sha1_final(unsigned char *hash, git_hash_ctx *ctx)
 
 static void git_hash_unknown_init(git_hash_ctx *ctx)
 {
-	die("trying to init unknown hash");
+	BUG("trying to init unknown hash");
 }
 
 static void git_hash_unknown_update(git_hash_ctx *ctx, const void *data, size_t len)
 {
-	die("trying to update unknown hash");
+	BUG("trying to update unknown hash");
 }
 
 static void git_hash_unknown_final(unsigned char *hash, git_hash_ctx *ctx)
 {
-	die("trying to finalize unknown hash");
+	BUG("trying to finalize unknown hash");
 }
 
 const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = {
@@ -379,7 +379,7 @@ static int alt_odb_usable(struct raw_object_store *o,
 	/* Detect cases where alternate disappeared */
 	if (!is_directory(path->buf)) {
 		error("object directory %s does not exist; "
-		      "check .git/objects/info/alternates.",
+		      "check .git/objects/info/alternates",
 		      path->buf);
 		return 0;
 	}

diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
@@ -390,7 +390,7 @@ test_expect_success 'Query "master@{2005-05-26 23:33:01}" (middle of history wit
 	test_when_finished "rm -f o e" &&
 	git rev-parse --verify "master@{2005-05-26 23:33:01}" >o 2>e &&
 	test $B = $(cat o) &&
-	test "warning: Log for ref $m has gap after $gd." = "$(cat e)"
+	test "warning: log for ref $m has gap after $gd" = "$(cat e)"
 '
 test_expect_success 'Query "master@{2005-05-26 23:38:00}" (middle of history)' '
 	test_when_finished "rm -f o e" &&
@@ -408,7 +408,7 @@ test_expect_success 'Query "master@{2005-05-28}" (past end of history)' '
 	test_when_finished "rm -f o e" &&
 	git rev-parse --verify "master@{2005-05-28}" >o 2>e &&
 	test $D = $(cat o) &&
-	test "warning: Log for ref $m unexpectedly ended on $ld." = "$(cat e)"
+	test "warning: log for ref $m unexpectedly ended on $ld" = "$(cat e)"
 '
 
 rm -f .git/$m .git/logs/$m expect
@@ -650,7 +650,7 @@ test_expect_success 'stdin fails with duplicate refs' '
 	create $a $m
 	EOF
 	test_must_fail git update-ref --stdin <stdin 2>err &&
-	grep "fatal: multiple updates for ref '"'"'$a'"'"' not allowed." err
+	grep "fatal: multiple updates for ref '"'"'$a'"'"' not allowed" err
 '
 
 test_expect_success 'stdin create ref works' '
@@ -1052,7 +1052,7 @@ test_expect_success 'stdin -z fails option with unknown name' '
 test_expect_success 'stdin -z fails with duplicate refs' '
 	printf $F "create $a" "$m" "create $b" "$m" "create $a" "$m" >stdin &&
 	test_must_fail git update-ref -z --stdin <stdin 2>err &&
-	grep "fatal: multiple updates for ref '"'"'$a'"'"' not allowed." err
+	grep "fatal: multiple updates for ref '"'"'$a'"'"' not allowed" err
 '
 
 test_expect_success 'stdin -z create ref works' '

diff --git a/t/t3005-ls-files-relative.sh b/t/t3005-ls-files-relative.sh
@@ -44,7 +44,7 @@ test_expect_success 'ls-files -c' '
 		cd top/sub &&
 		for f in ../y*
 		do
-			echo "error: pathspec $sq$f$sq did not match any file(s) known to git."
+			echo "error: pathspec $sq$f$sq did not match any file(s) known to git"
 		done >expect.err &&
 		echo "Did you forget to ${sq}git add${sq}?" >>expect.err &&
 		ls ../x* >expect.out &&
@@ -59,7 +59,7 @@ test_expect_success 'ls-files -o' '
 		cd top/sub &&
 		for f in ../x*
 		do
-			echo "error: pathspec $sq$f$sq did not match any file(s) known to git."
+			echo "error: pathspec $sq$f$sq did not match any file(s) known to git"
 		done >expect.err &&
 		echo "Did you forget to ${sq}git add${sq}?" >>expect.err &&
 		ls ../y* >expect.out &&

diff --git a/t/t5801-remote-helpers.sh b/t/t5801-remote-helpers.sh
@@ -126,15 +126,15 @@ test_expect_success 'forced push' '
 test_expect_success 'cloning without refspec' '
 	GIT_REMOTE_TESTGIT_REFSPEC="" \
 	git clone "testgit::${PWD}/server" local2 2>error &&
-	grep "This remote helper should implement refspec capability" error &&
+	grep "this remote helper should implement refspec capability" error &&
 	compare_refs local2 HEAD server HEAD
 '
 
 test_expect_success 'pulling without refspecs' '
 	(cd local2 &&
 	git reset --hard &&
 	GIT_REMOTE_TESTGIT_REFSPEC="" git pull 2>../error) &&
-	grep "This remote helper should implement refspec capability" error &&
+	grep "this remote helper should implement refspec capability" error &&
 	compare_refs local2 HEAD server HEAD
 '
 
@@ -246,7 +246,7 @@ test_expect_success 'proper failure checks for fetching' '
 	(cd local &&
 	test_must_fail env GIT_REMOTE_TESTGIT_FAILURE=1 git fetch 2>error &&
 	cat error &&
-	grep -q "Error while running fast-import" error
+	grep -q "error while running fast-import" error
 	)
 '
 

diff --git a/t/t7063-status-untracked-cache.sh b/t/t7063-status-untracked-cache.sh
@@ -666,7 +666,7 @@ test_expect_success 'test ident field is working' '
 	mkdir ../other_worktree &&
 	cp -R done dthree dtwo four three ../other_worktree &&
 	GIT_WORK_TREE=../other_worktree git status 2>../err &&
-	echo "warning: Untracked cache is disabled on this system or location." >../expect &&
+	echo "warning: untracked cache is disabled on this system or location" >../expect &&
 	test_i18ncmp ../expect ../err
 '
 

diff --git a/transport-helper.c b/transport-helper.c
@@ -48,7 +48,7 @@ static void sendline(struct helper_data *helper, struct strbuf *buffer)
 	if (debug)
 		fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
 	if (write_in_full(helper->helper->in, buffer->buf, buffer->len) < 0)
-		die_errno("Full write to remote helper failed");
+		die_errno("full write to remote helper failed");
 }
 
 static int recvline_fh(FILE *helper, struct strbuf *buffer)
@@ -77,7 +77,7 @@ static void write_constant(int fd, const char *str)
 	if (debug)
 		fprintf(stderr, "Debug: Remote helper: -> %s", str);
 	if (write_in_full(fd, str, strlen(str)) < 0)
-		die_errno("Full write to remote helper failed");
+		die_errno("full write to remote helper failed");
 }
 
 static const char *remove_ext_force(const char *url)
@@ -129,7 +129,7 @@ static struct child_process *get_helper(struct transport *transport)
 
 	code = start_command(helper);
 	if (code < 0 && errno == ENOENT)
-		die("Unable to find remote helper for '%s'", data->name);
+		die("unable to find remote helper for '%s'", data->name);
 	else if (code != 0)
 		exit(code);
 
@@ -145,7 +145,7 @@ static struct child_process *get_helper(struct transport *transport)
 	 */
 	duped = dup(helper->out);
 	if (duped < 0)
-		die_errno("Can't dup helper output fd");
+		die_errno("can't dup helper output fd");
 	data->out = xfdopen(duped, "r");
 
 	write_constant(helper->in, "capabilities\n");
@@ -196,13 +196,13 @@ static struct child_process *get_helper(struct transport *transport)
 		} else if (starts_with(capname, "no-private-update")) {
 			data->no_private_update = 1;
 		} else if (mandatory) {
-			die("Unknown mandatory capability %s. This remote "
-			    "helper probably needs newer version of Git.",
+			die("unknown mandatory capability %s; this remote "
+			    "helper probably needs newer version of Git",
 			    capname);
 		}
 	}
 	if (!data->rs.nr && (data->import || data->bidi_import || data->export)) {
-		warning("This remote helper should implement refspec capability.");
+		warning("this remote helper should implement refspec capability");
 	}
 	strbuf_release(&buf);
 	if (debug)
@@ -476,7 +476,7 @@ static int fetch_with_import(struct transport *transport,
 	get_helper(transport);
 
 	if (get_importer(transport, &fastimport))
-		die("Couldn't run fast-import");
+		die("couldn't run fast-import");
 
 	for (i = 0; i < nr_heads; i++) {
 		posn = to_fetch[i];
@@ -499,7 +499,7 @@ static int fetch_with_import(struct transport *transport,
 	 */
 
 	if (finish_command(&fastimport))
-		die("Error while running fast-import");
+		die("error while running fast-import");
 
 	/*
 	 * The fast-import stream of a remote helper that advertises
@@ -528,7 +528,7 @@ static int fetch_with_import(struct transport *transport,
 			private = xstrdup(name);
 		if (private) {
 			if (read_ref(private, &posn->old_oid) < 0)
-				die("Could not read ref %s", private);
+				die("could not read ref %s", private);
 			free(private);
 		}
 	}
@@ -554,7 +554,7 @@ static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
 	 */
 	duped = dup(helper->out);
 	if (duped < 0)
-		die_errno("Can't dup helper output fd");
+		die_errno("can't dup helper output fd");
 	input = xfdopen(duped, "r");
 	setvbuf(input, NULL, _IONBF, 0);
 
@@ -573,7 +573,7 @@ static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
 			fprintf(stderr, "Debug: Falling back to dumb "
 				"transport.\n");
 	} else {
-		die("Unknown response to connect: %s",
+		die("unknown response to connect: %s",
 			cmdbuf->buf);
 	}
 
@@ -595,9 +595,9 @@ static int process_connect_service(struct transport *transport,
 	if (strcmp(name, exec)) {
 		int r = set_helper_option(transport, "servpath", exec);
 		if (r > 0)
-			warning("Setting remote service path not supported by protocol.");
+			warning("setting remote service path not supported by protocol");
 		else if (r < 0)
-			warning("Invalid remote service path.");
+			warning("invalid remote service path");
 	}
 
 	if (data->connect) {
@@ -640,10 +640,10 @@ static int connect_helper(struct transport *transport, const char *name,
 	/* Get_helper so connect is inited. */
 	get_helper(transport);
 	if (!data->connect)
-		die("Operation not supported by protocol.");
+		die("operation not supported by protocol");
 
 	if (!process_connect_service(transport, name, exec))
-		die("Can't connect to subservice %s.", name);
+		die("can't connect to subservice %s", name);
 
 	fd[0] = data->helper->out;
 	fd[1] = data->helper->in;
@@ -978,12 +978,12 @@ static int push_refs_with_export(struct transport *transport,
 	}
 
 	if (get_exporter(transport, &exporter, &revlist_args))
-		die("Couldn't run fast-export");
+		die("couldn't run fast-export");
 
 	string_list_clear(&revlist_args, 1);
 
 	if (finish_command(&exporter))
-		die("Error while running fast-export");
+		die("error while running fast-export");
 	if (push_update_refs_status(data, remote_refs, flags))
 		return 1;
 
@@ -1070,7 +1070,7 @@ static struct ref *get_refs_list(struct transport *transport, int for_push,
 
 		eov = strchr(buf.buf, ' ');
 		if (!eov)
-			die("Malformed response in ref list: %s", buf.buf);
+			die("malformed response in ref list: %s", buf.buf);
 		eon = strchr(eov + 1, ' ');
 		*eov = '\0';
 		if (eon)
@@ -1084,7 +1084,7 @@ static struct ref *get_refs_list(struct transport *transport, int for_push,
 			if (has_attribute(eon + 1, "unchanged")) {
 				(*tail)->status |= REF_STATUS_UPTODATE;
 				if (read_ref((*tail)->name, &(*tail)->old_oid) < 0)
-					die(_("Could not read ref %s"),
+					die(_("could not read ref %s"),
 					    (*tail)->name);
 			}
 		}
@@ -1322,11 +1322,11 @@ static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
 	err = pthread_create(&gtp_thread, NULL, udt_copy_task_routine,
 		&s->gtp);
 	if (err)
-		die("Can't start thread for copying data: %s", strerror(err));
+		die("can't start thread for copying data: %s", strerror(err));
 	err = pthread_create(&ptg_thread, NULL, udt_copy_task_routine,
 		&s->ptg);
 	if (err)
-		die("Can't start thread for copying data: %s", strerror(err));
+		die("can't start thread for copying data: %s", strerror(err));
 
 	ret |= tloop_join(gtp_thread, "Git to program copy");
 	ret |= tloop_join(ptg_thread, "Program to git copy");
@@ -1385,7 +1385,7 @@ static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
 	/* Fork thread #1: git to program. */
 	pid1 = fork();
 	if (pid1 < 0)
-		die_errno("Can't start thread for copying data");
+		die_errno("can't start thread for copying data");
 	else if (pid1 == 0) {
 		udt_kill_transfer(&s->ptg);
 		exit(udt_copy_task_routine(&s->gtp) ? 0 : 1);
@@ -1394,7 +1394,7 @@ static int tloop_spawnwait_tasks(struct bidirectional_transfer_state *s)
 	/* Fork thread #2: program to git. */
 	pid2 = fork();
 	if (pid2 < 0)
-		die_errno("Can't start thread for copying data");
+		die_errno("can't start thread for copying data");
 	else if (pid2 == 0) {
 		udt_kill_transfer(&s->gtp);
 		exit(udt_copy_task_routine(&s->ptg) ? 0 : 1);

diff --git a/transport.c b/transport.c
@@ -139,7 +139,7 @@ static struct ref *get_refs_from_bundle(struct transport *transport,
 		close(data->fd);
 	data->fd = read_bundle_header(transport->url, &data->header);
 	if (data->fd < 0)
-		die ("Could not read bundle '%s'.", transport->url);
+		die("could not read bundle '%s'", transport->url);
 	for (i = 0; i < data->header.references.nr; i++) {
 		struct ref_list_entry *e = data->header.references.list + i;
 		struct ref *ref = alloc_ref(e->name);
@@ -875,7 +875,7 @@ struct transport *transport_get(struct remote *remote, const char *url)
 	ret->progress = isatty(2);
 
 	if (!remote)
-		die("No remote provided to transport_get()");
+		BUG("No remote provided to transport_get()");
 
 	ret->got_remote_refs = 0;
 	ret->remote = remote;
@@ -1143,7 +1143,7 @@ int transport_push(struct transport *transport,
 						      transport->push_options,
 						      pretend)) {
 				oid_array_clear(&commits);
-				die("Failed to push all needed submodules!");
+				die("failed to push all needed submodules!");
 			}
 			oid_array_clear(&commits);
 		}
@@ -1265,7 +1265,7 @@ int transport_connect(struct transport *transport, const char *name,
 	if (transport->vtable->connect)
 		return transport->vtable->connect(transport, name, exec, fd);
 	else
-		die("Operation not supported by protocol");
+		die("operation not supported by protocol");
 }
 
 int transport_disconnect(struct transport *transport)