Run hooks on rcdn as indicated by the manpage

- Make sure IFS in rcup and rcdn isn't left in an incorrect state when
  the output of lsrc is empty.
- Add tests to check that hooks run on rcdn and rcup by default.

bin/rcdn.in

@@ -31,7 +31,7 @@ handle_command_line() {
   local arg_tags=
   local verbosity=0
   local version=0
-  local run_hooks=0
+  local run_hooks=1
   local dotfiles_dirs=
   local files=
   local excludes=
@@ -124,4 +124,5 @@ for dest_and_src in $dests_and_srcs; do
   remove_link "$dest" "$dest" "$sigil"
 done
 
+IFS="$saved_ifs"
 run_hooks post down

bin/rcup.in

@@ -302,4 +302,5 @@ for dest_and_src in $dests_and_srcs; do
   handle_file "$GENERATE" "$src" "$dest" "$sigil"
 done
 
+IFS="$saved_ifs"
 run_hooks post up

test/Makefile.am

@@ -24,7 +24,10 @@ TESTS = \
 	rcup-hostname.t \
 	rcup-standalone.t \
 	rcup-symlink-dirs.t \
-	rcup-usage.t
+	rcup-usage.t \
+	rcdn-hooks.t \
+	rcup-hooks.t
+
 
 dist_check_SCRIPTS = $(TESTS)
 dist_check_DATA = helper.sh

test/rcdn-hooks.t

@@ -0,0 +1,19 @@
+  $ . "$TESTDIR/helper.sh"
+
+Pre-down and post-down hooks should run by default
+
+  $ mkdir -p .dotfiles/hooks
+  > touch .dotfiles/hooks/pre-down .dotfiles/hooks/post-down
+  > chmod +x .dotfiles/hooks/pre-down .dotfiles/hooks/post-down
+
+  $ echo 'echo "example" > /tmp/test' > .dotfiles/hooks/pre-down
+  > echo 'cat /tmp/test; rm /tmp/test' > .dotfiles/hooks/post-down
+
+  $ rcdn
+  example
+
+Ensure that hooks run when output of lsrc is non-empty
+  $ touch .dotfiles/testrc
+  > rcup
+  > rcdn
+  example

test/rcup-hooks.t

@@ -0,0 +1,18 @@
+  $ . "$TESTDIR/helper.sh"
+
+Pre-up and post-up hooks should run by default
+
+  $ mkdir -p .dotfiles/hooks
+  > touch .dotfiles/hooks/pre-up .dotfiles/hooks/post-up
+  > chmod +x .dotfiles/hooks/pre-up .dotfiles/hooks/post-up
+
+  $ echo 'echo "example" > /tmp/test' > .dotfiles/hooks/pre-up
+  > echo 'cat /tmp/test; rm /tmp/test' > .dotfiles/hooks/post-up
+
+  $ rcup
+  example
+
+Ensure that hooks run when output of lsrc is non-empty
+  $ touch .dotfiles/testrc
+  > rcup
+  example