diff --git a/etc/README.md b/etc/README.md
index 63411a6..95ad13e 100644
--- a/etc/README.md
+++ b/etc/README.md
@@ -909,6 +909,8 @@ usage: ./pkgtool.sh [-a nt32|nt64] [-b debug|release] [-i|-m <dname> -M <dname>|
         -i                    List package variables and dependencies of single named package.
         -m <dname>            Setup package archives mirror in <dname> and/or
         -M <dname>            Setup Git repositories mirror in <dname>
+                              Specify "" or '' as <dname> to default to the defaults in
+                              ${HOME}/pkgtool.vars, if present.
         -r                    List reverse dependencies of single named package.
         -R                    List full reverse dependencies of single named package.
         -t                    Produce tarball of package build root directory and build log
@@ -921,7 +923,12 @@ usage: ./pkgtool.sh [-a nt32|nt64] [-b debug|release] [-i|-m <dname> -M <dname>|
   
 > N.B. When using ``pkgtool.sh`` on a build w/ build variables (see section [4.2](#42-build-variables))
 overriden on the command line or via the environment, ensure that they are included in the
-``pkgtool.sh`` command line, preceding the package name, or exported, respectively.
+``pkgtool.sh`` command line, preceding the package name, or exported, respectively.  
+  
+> N.B. ``pkgtool.sh`` will source the ``${HOME}/pkgtool.vars`` file, if present, on startup where the
+following option arguments may be set: ``-a nt32|nt64`` by setting ``ARCH=...``, ``-b debug|release``
+by setting ``BUILD_KIND=...``, ``-m <dname>`` by setting ``ARG_MIRROR_DNAME=...``, and ``-M <dname>``
+by setting ``ARG_MIRROR_DNAME_GIT=...``.  
   
 [Back to top](#table-of-contents)
 
diff --git a/etc/pkgtool.usage b/etc/pkgtool.usage
index 6c86e86..446ac3a 100644
--- a/etc/pkgtool.usage
+++ b/etc/pkgtool.usage
@@ -6,6 +6,8 @@
         -i                List package variables and dependencies of single named package.
         -m <dname>        Setup package archives mirror in <dname> and/or
         -M <dname>        Setup Git repositories mirror in <dname>
+                          Specify "" or '' as <dname> to default to the defaults in
+                          ${HOME}/pkgtool.vars, if present.
         -r                List reverse dependencies of single named package.
         -R                List recursive reverse dependencies of single named package.
         -t                Produce tarball of package build root directory and build log
diff --git a/pkgtool.sh b/pkgtool.sh
index 24f0233..03efe32 100755
--- a/pkgtool.sh
+++ b/pkgtool.sh
@@ -15,6 +15,10 @@ pkgtoolp_init() {
 		_pi_fname="" _pi_rc=0;
 	shift;
 
+	if [ -e "${HOME}/pkgtool.vars" ]; then
+		. "${HOME}/pkgtool.vars" || exit 1;
+	fi;
+
 	if ! . "${0%/*}/subr.ex/ex_init.subr"; then
 		_pi_rc=1;
 		_pi_status='failed to source \`'"${0%/*}/subr/ex_init.subr"\';
@@ -80,8 +84,8 @@ pkgtoolp_init_getopts_fn() {
 		: ${ARCH:="nt64"};
 		: ${BUILD_KIND:="debug"};
 
-		ARG_INFO=0; ARG_MIRROR=0; ARG_MIRROR_DNAME=""; ARG_MIRROR_DNAME_GIT="";
-		ARG_RDEPENDS=0; ARG_RDEPENDS_FULL=0; ARG_TARBALL=0; ARG_VERBOSE=0;
+		ARG_INFO=0; ARG_MIRROR=0; ARG_RDEPENDS=0;
+		ARG_RDEPENDS_FULL=0; ARG_TARBALL=0; ARG_VERBOSE=0;
 		;;
 
 	longopt)
@@ -98,8 +102,20 @@ pkgtoolp_init_getopts_fn() {
 		b)	BUILD_KIND="${OPTARG}"; _ppigf_shiftfl=2; ;;
 		h)	cat etc/pkgtool.usage; exit 0; ;;
 		i)	ARG_INFO=1; _ppigf_shiftfl=1; ;;
-		m)	ARG_MIRROR=1; ARG_MIRROR_DNAME="${OPTARG}"; _ppigf_shiftfl=2; ;;
-		M)	ARG_MIRROR=1; ARG_MIRROR_DNAME_GIT="${OPTARG}"; _ppigf_shiftfl=2; ;;
+		m)	ARG_MIRROR=1;
+			if [ "${OPTARG:+1}" = 1 ]; then
+				ARG_MIRROR_DNAME="${OPTARG}";
+			elif [ "${ARG_MIRROR_DNAME:+1}" != 1 ]; then
+				rtl_setrstatus "${_ppigf_rstatus}" 'missing -m argument and no default present.';
+			fi;
+			_ppigf_shiftfl=2; ;;
+		M)	ARG_MIRROR=1;
+			if [ "${OPTARG:+1}" = 1 ]; then
+				ARG_MIRROR_DNAME_GIT="${OPTARG}";
+			elif [ "${ARG_MIRROR_DNAME_GIT:+1}" != 1 ]; then
+				rtl_setrstatus "${_ppigf_rstatus}" 'missing -M argument and no default present.';
+			fi;
+			_ppigf_shiftfl=2; ;;
 		r)	ARG_RDEPENDS=1; _ppigf_shiftfl=1; ;;
 		R)	ARG_RDEPENDS_FULL=1; _ppigf_shiftfl=1; ;;
 		t)	ARG_TARBALL=1; _ppigf_shiftfl=1; ;;