diff --git a/subr/build_init.subr b/subr/build_init.subr
index 6d1635d..49f0dca 100644
--- a/subr/build_init.subr
+++ b/subr/build_init.subr
@@ -91,9 +91,9 @@ buildp_init_env() {
 	elif ! umask 022; then
 		printf "Error: failed to set umask(2).\n" >&2; exit 1;
 	elif ! BUILD_HNAME="$(hostname)"; then
-		_rc=1; _status="Error: failed to obtain hostname.";
+		printf "Error: failed to obtain hostname." >&2; exit 1;
 	elif ! BUILD_USER="$(id -nu)"; then
-		_rc=1; _status="Error: failed to obtain username.";
+		printf "Error: failed to obtain username." >&2; exit 1;
 	else	for _fname in $(find subr -name *.subr); do
 			if ! . "${_fname}"; then
 				printf "Error: failed to source \`%s'.\n" "${_fname}"; exit 1;
@@ -215,34 +215,36 @@ buildp_init_getopts() {
 	return "${_rc}";
 };
 
+buildp_init_getopts_help() {
+	local _opt="";
+	while getopts a:b:C:D:Fhp:Pr:R _opt 2>/dev/null; do
+	case "${_opt}" in
+	h)	cat etc/build.usage; exit 0; ;;
+	esac; done; shift $((${OPTIND}-1));
+};
+
 buildp_init_prereqs() {
-	local _cmd="" _cmds_missing="" _rc=0; _status="";
-	for _cmd in	\
+	if ! rtl_check_prereqs \
 			awk bunzip2 bzip2 cat chmod cmake cp date find flock	\
 			g++ gcc git grep gunzip gzip hostname id install kill	\
 			ln lzip make mkdir mkfifo mktemp mv paste patch perl	\
 			pgrep pkill printf readlink rm sed sha256sum sort	\
-			tail tar test touch tr uniq wget xz zip; do
-		if ! which "${_cmd}" >/dev/null 2>&1; then
-			_cmds_missing="${_cmds_missing:+${_cmds_missing} }${_cmd}";
-		fi;
-	done;
-	if [ -n "${_cmds_missing}" ]; then
-		_rc=1; _status="Error: missing prerequisite package(s): ${_cmds_missing}";
+			tail tar test touch tr uniq wget xz zip; then
+		printf "%s\n" "${_status}" >&2; exit 1;
 	elif ! (FNAME="$(mktemp)" && { trap "rm -f \"\${FNAME}\"" EXIT;		\
 			sed -i'' -e '' "${FNAME}" >/dev/null 2>&1; }); then
-		_rc=1; _status="Error: sed(1) in \${PATH} does not support the \`-i' option.";
+		printf "Error: sed(1) in \${PATH} does not support the \`-i' option.\n" >&2; exit 1;
 	fi;
-	return "${_rc}";
 };
 
 build_init() {
 	local _rc=0; _status="";
-	if ! buildp_init_env		\
-	|| ! buildp_init_getopts "${@}"	\
-	|| ! buildp_init_prereqs	\
-	|| ! ex_pkg_load_vars		\
-	|| ! buildp_init_args		\
+	if ! buildp_init_env			\
+	|| ! buildp_init_getopts_help "${@}"	\
+	|| ! buildp_init_prereqs		\
+	|| ! buildp_init_getopts "${@}"		\
+	|| ! ex_pkg_load_vars			\
+	|| ! buildp_init_args			\
 	|| ! buildp_init_files; then
 		_rc=1; _status="${_status}";
 	fi; return "${_rc}";
diff --git a/subr/pkgtool_init.subr b/subr/pkgtool_init.subr
index 309dc61..f5eb21f 100644
--- a/subr/pkgtool_init.subr
+++ b/subr/pkgtool_init.subr
@@ -74,7 +74,7 @@ pkgtoolp_init_getopts() {
 		done;
 		if [ "${_rc:-0}" -eq 0 ]; then
 			if [ "${#}" -ne 1 ]\
-			&& [ -z "${PKGTOOL_PKG_NAME}" ]; then
+			&& [ -z "${PKGTOOL_PKG_NAME:-}" ]; then
 				_rc=1; _status="Error: missing package name.";
 			elif [ "${#}" -eq 1 ]; then
 				PKGTOOL_PKG_NAME="${1}"; export PKGTOOL_PKG_NAME;
@@ -83,29 +83,32 @@ pkgtoolp_init_getopts() {
 	fi; return "${_rc}";
 };
 
+pkgtoolp_init_getopts_help() {
+	local _opt="";
+	while getopts a:b:hirst _opt 2>/dev/null; do
+	case "${_opt}" in
+	h)	cat etc/build.usage; exit 0; ;;
+	esac; done; shift $((${OPTIND}-1));
+};
+
 pkgtoolp_init_prereqs() {
-	local _cmd="" _cmds_missing="" _rc=0; _status="";
-	for _cmd in	\
+	if ! rtl_check_prereqs \
 			awk bzip2 cat chmod cp date find grep hostname mkdir	\
 			mktemp mv paste printf readlink rm sed sort tar test	\
-			touch tr uniq; do
-		if ! which "${_cmd}" >/dev/null 2>&1; then
-			_cmds_missing="${_cmds_missing:+${_cmds_missing} }${_cmd}";
-		fi;
-	done;
-	if [ -n "${_cmds_missing}" ]; then
-		_rc=1; _status="Error: missing prerequisite package(s): ${_cmds_missing}";
+			touch tr uniq; then
+		printf "%s\n" "${_status}" >&2; exit 1;
 	elif ! (FNAME="$(mktemp)" && { trap "rm -f \"\${FNAME}\"" EXIT;		\
 			sed -i'' -e '' "${FNAME}" >/dev/null 2>&1; }); then
-		_rc=1; _status="Error: sed(1) in \${PATH} does not support the \`-i' option.";
-	fi; return "${_rc}";
+		printf "Error: sed(1) in \${PATH} does not support the \`-i' option.\n" >&2; exit 1;
+	fi;
 };
 
 pkgtool_init() {
 	local _fname="" _rc=0; _status="";
 	if ! pkgtoolp_init_env			\
-	|| ! pkgtoolp_init_getopts "${@}"	\
+	|| ! pkgtoolp_init_getopts_help "${@}"	\
 	|| ! pkgtoolp_init_prereqs		\
+	|| ! pkgtoolp_init_getopts "${@}"	\
 	|| ! ex_pkg_load_vars			\
 	|| ! pkgtoolp_init_args; then
 		_rc=1; _status="${_status}";
diff --git a/subr/rtl_complex.subr b/subr/rtl_complex.subr
index 8aa59be..2c23cfe 100644
--- a/subr/rtl_complex.subr
+++ b/subr/rtl_complex.subr
@@ -15,6 +15,19 @@ rtl_check_path_vars() {
 	return "${_rc}";
 };
 
+rtl_check_prereqs() {
+	local _cmd="" _cmds_missing="" _rc=0; _status="";
+	for _cmd in "${@}"; do
+		if ! which "${_cmd}" >/dev/null 2>&1; then
+			_cmds_missing="${_cmds_missing:+${_cmds_missing} }${_cmd}";
+		fi;
+	done;
+	if [ -n "${_cmds_missing}" ]; then
+		_rc=1; _status="Error: missing prerequisite package(s): ${_cmds_missing}";
+	fi;
+	return "${_rc}";
+};
+
 rtl_clean_env() {
 	local _env_vars_except="${1}" _env_var="" _env_vars="";
 	_env_vars="$(export | sed -ne '/^export/{s/^export //;s/=.*$//p}')";
@@ -173,6 +186,29 @@ rtl_kill_tree() {
 	fi;
 };
 
+rtl_prompt() {
+	local _fmt="${1}" _choice=""; shift;
+	printf "${_fmt}? (y|N) " "${@}";
+	read -r _choice;
+	case "${_choice}" in
+	[yY])	_choice=1; ;;
+	*)	_choice=0; ;;
+	esac;
+	return "${_choice}";
+};
+
+rtl_rc() {
+	local _nflag="${1}" _cmd="${2}"; shift 2;
+	case "${_nflag}" in
+	1)	     if [ "${#}" -gt 0 ]; then
+			rtl_log_msg notice "Command line: %s %s" "${_cmd}" "${*}";
+		else
+			rtl_log_msg notice "Command line: %s" "${_cmd}";
+		fi; ;;
+	*)	"${_cmd}" "${@}";
+	esac;
+};
+
 rtl_run_cmd_unsplit() {
 	local _cmd="${1}" _cmdline="" _rc="" IFS; shift;
 	while [ ${#} -gt 0 ]; do