--- functions.stock 
+++ functions.my 
@@ -452,8 +452,54 @@
 	echo $$ >"$pidfile"
 }
 
+#get_packages()
+print_uris()
+{
+	[ -n "$APT_CONFIG" ] || Fatal "APT_CONFIG undefined."
+	local out
+	if ! out="$("$prog_apt_get" -q=2 -y --print-uris install -- "$@" 2>&1)"; then
+		printf %s\\n "$out" >&2
+		Fatal "failed to calculate package file list."
+	fi
+    local grep_pattern="^'\\(file\\|copy\\):"
+    local filenames
+    if ! filenames="$(printf %s "$out" | grep -v "$grep_pattern" | cut -d' ' -f2)"; then
+		printf %s\\n "$out" >&2
+		Fatal "failed to filter package file list."
+    fi
+    for f in $filenames; do
+        [ -r "/var/cache/apt/archives/$f" ] &&
+            cp -- "/var/cache/apt/archives/$f" \
+                "$aptbox/var/cache/apt/archives/" &&
+            continue
+        [ -r "$aptbox/../cache/archives/$f" ] &&
+            cp -- "$aptbox/../cache/archives/$f" \
+                "$aptbox/var/cache/apt/archives/" &&
+            continue
+    done
+    if ! "$prog_apt_get" -y -d install -- "$@" >&2; then
+        printf %s\\n "$out" >&2
+        Fatal "failed to download packages."
+    fi
+    mkdir -p $aptbox/../cache/archives
+
+	local local_uris
+	local sed_pattern="'\\(file\\|copy\\):\\([^']\\+\\)' .*"
+	if ! local_uris="$(printf %s "$out" |sed -ne "s/^$sed_pattern/\\2/pg")"; then
+		printf %s\\n "$out" >&2
+		Fatal "failed to filter package file list."
+	fi
+
+	printf %s\\n "$local_uris" &&
+    for f in $filenames; do
+        local ff="$aptbox/var/cache/apt/archives/$f"
+        cp -- $ff "$aptbox/../cache/archives/"
+        printf %s\\n "$ff"
+    done && Verbose "packages are ready to install."
+}
+
 # assumed: defined APT_CONFIG, prog_apt_get
-print_uris()
+old_print_uris()
 {
 	[ -n "$APT_CONFIG" ] || Fatal "APT_CONFIG undefined."
 	local out