diff --git a/src/lib/dotify-action.sh b/src/lib/dotify-action.sh
index eb5268c..bb65a86 100644
--- a/src/lib/dotify-action.sh
+++ b/src/lib/dotify-action.sh
@@ -1,17 +1,26 @@
 dotify-action() {
   local action="$1"
-  local source="$2"
-  local target="$3"
+
+  if [ $# -lt 3 ]; then
+    local target="$2"
+  else
+    local source="$2"
+    local target="$3"
+  fi
 
   if [ "$action" == "default" ]; then
     action="$DOTIFY_OPT_DEFAULT_ACTION"
   fi
 
-  ! valid_action="$(command -v "dotify-action-${action}")"
+  ! local valid_action="$(command -v "dotify-action-${action}")"
   if [ -z "$valid_action" ]; then
     echo "ERROR: \"$action\" is not a valid action." >&2
     return 1
   fi
 
-  dotify-action-${action} "$source" "$target"
+  if [ -n "$source" ]; then
+    dotify-action-${action} "$DOTIFY_RUN_MODE" "$target" "$source"
+  else
+    dotify-action-${action} "$DOTIFY_RUN_MODE" "$target"
+  fi
 }
diff --git a/test/lib/dotify-action-test.sh b/test/lib/dotify-action-test.sh
index 85b7f20..89d716a 100755
--- a/test/lib/dotify-action-test.sh
+++ b/test/lib/dotify-action-test.sh
@@ -6,7 +6,8 @@ source "../../src/lib/dotify-action.sh"
 # dotify-action() tests
 #
 
-# Set required option ENV
+# Set required environment variables.
+DOTIFY_RUN_MODE="install"
 DOTIFY_OPT_DEFAULT_ACTION="link"
 
 # Simple mock for link action.
@@ -16,10 +17,17 @@ dotify-action-link() {
 
 
 # Given a specific action.
-assert "dotify-action link ackrc .ackrc" "link stub: ackrc .ackrc"
+assert "dotify-action link ackrc .ackrc" "link stub: install .ackrc ackrc"
+
+# Given a specific action without a <source>.
+assert "dotify-action link .ackrc" "link stub: install .ackrc"
 
 # Given "default" action, it uses configured default action.
-assert "dotify-action default ackrc .ackrc" "link stub: ackrc .ackrc"
+assert "dotify-action default ackrc .ackrc" "link stub: install .ackrc ackrc"
+
+# Given "default" action without a <source>, it uses configured default
+# action.
+assert "dotify-action default .ackrc" "link stub: install .ackrc"
 
 # Given a invalid action.
 assert_raises "dotify-action foo ackrc .ackrc" 1