diff --git a/Makefile b/Makefile
index dff500fbc..cca33607e 100644
--- a/Makefile
+++ b/Makefile
@@ -214,6 +214,14 @@ install:
 	    CORE_PACKAGESITE=${CORE_PACKAGESITE} \
 	    CORE_REPOSITORY=${CORE_REPOSITORY}
 
+collect:
+	@(cd ${.CURDIR}/src; find * -type f) | while read FILE; do \
+		if [ -f ${DESTDIR}${LOCALBASE}/$${FILE} ]; then \
+			tar -C ${DESTDIR}${LOCALBASE} -cpf - $${FILE} | \
+			    tar -C ${.CURDIR}/src -xpf -; \
+		fi; \
+	done
+
 bootstrap:
 	@${MAKE} -C ${.CURDIR}/src install-bootstrap DESTDIR=${DESTDIR} \
 	    NO_SAMPLE=please CORE_PACKAGESITE=${CORE_PACKAGESITE} \
diff --git a/README.md b/README.md
index 809469854..3f9b12d05 100644
--- a/README.md
+++ b/README.md
@@ -83,6 +83,11 @@ make upgrade
 Upgrade will run the package build and replace the currently installed
 package in the system.
 
+make collect
+------------
+
+Fetch changes from the running system for all known files.
+
 make lint
 ---------