diff --git a/gitk b/gitk
index db61a15da1..42e96d0e49 100755
--- a/gitk
+++ b/gitk
@@ -32,10 +32,29 @@ proc parse_args {rargs} {
     return $parsed_args
 }
 
-proc getcommits {rargs} {
-    global oldcommits commits commfd phase canv mainfont env
+proc start_rev_list {rlargs} {
     global startmsecs nextupdate ncmupdate
-    global ctext maincursor textcursor leftover gitencoding
+    global commfd leftover gitencoding
+
+    set startmsecs [clock clicks -milliseconds]
+    set nextupdate [expr {$startmsecs + 100}]
+    set ncmupdate 1
+    if [catch {
+	set commfd [open [concat | git-rev-list --header --topo-order \
+			      --parents $rlargs] r]
+    } err] {
+	puts stderr "Error executing git-rev-list: $err"
+	exit 1
+    }
+    set leftover {}
+    fconfigure $commfd -blocking 0 -translation lf -encoding $gitencoding
+    fileevent $commfd readable [list getcommitlines $commfd]
+    . config -cursor watch
+    settextcursor watch
+}
+
+proc getcommits {rargs} {
+    global oldcommits commits phase canv mainfont env
 
     # check that we can find a .git directory somewhere...
     set gitdir [gitdir]
@@ -46,24 +65,10 @@ proc getcommits {rargs} {
     set oldcommits {}
     set commits {}
     set phase getcommits
-    set startmsecs [clock clicks -milliseconds]
-    set nextupdate [expr {$startmsecs + 100}]
-    set ncmupdate 1
-    set parsed_args [parse_args $rargs]
-    if [catch {
-	set commfd [open "|git-rev-list --header --topo-order --parents $parsed_args" r]
-    } err] {
-	puts stderr "Error executing git-rev-list: $err"
-	exit 1
-    }
-    set leftover {}
-    fconfigure $commfd -blocking 0 -translation lf -encoding $gitencoding
-    fileevent $commfd readable [list getcommitlines $commfd]
+    start_rev_list [parse_args $rargs]
     $canv delete all
     $canv create text 3 3 -anchor nw -text "Reading commits..." \
 	-font $mainfont -tags textitems
-    . config -cursor watch
-    settextcursor watch
 }
 
 proc getcommitlines {commfd}  {
@@ -3684,20 +3689,7 @@ proc updatecommits {rargs} {
     }
 
     readrefs
-    if [catch {
-	set commfd [open "|git-rev-list --header --topo-order --parents $ignoreold $args" r]
-    } err] {
-	puts stderr "Error executing git-rev-list: $err"
-	exit 1
-    }
-    set startmsecs [clock clicks -milliseconds]
-    set nextupdate [expr $startmsecs + 100]
-    set ncmupdate 1
-    set leftover {}
-    fconfigure $commfd -blocking 0 -translation lf
-    fileevent $commfd readable [list getcommitlines $commfd]
-    . config -cursor watch
-    settextcursor watch
+    start_rev_list [concat $ignoreold $args]
 }
 
 proc showtag {tag isnew} {