Index: tools/tools/git/git-arc.1
===================================================================
--- tools/tools/git/git-arc.1
+++ tools/tools/git/git-arc.1
@@ -24,7 +24,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd May 14, 2021
+.Dd November 17, 2021
 .Dt GIT-ARC 1
 .Os
 .Sh NAME
@@ -36,6 +36,7 @@
 .Op Fl l
 .Op Fl r Ar reviewer1 Ns Op Cm \&, Ns Ar reviewer2 ...
 .Op Fl s Ar subscriber1 Ns Op Cm \&, Ns Ar subscriber2 ...
+.Op Fl p Ar parent
 .Op Ar commit Ns | Ns Ar commit-range
 .Nm
 .Cm list Ar commit Ns | Ns Ar commit-range
@@ -78,6 +79,10 @@
 .It Fl r Ar subscriber
 Add one or more subscribers, separated by commas, to revision(s) being created.
 Argument(s) must be existing Phabricator user or group.
+.It Fl p Ar parent
+Specify the parent of the first commit in the list.
+This is useful when adding more commits on top of the already existing
+stack in Phabricator.
 .El
 .It Cm list
 Print the associated Differential Revisions for the specified commits.
Index: tools/tools/git/git-arc.sh
===================================================================
--- tools/tools/git/git-arc.sh
+++ tools/tools/git/git-arc.sh
@@ -356,15 +356,19 @@
     local commit commits doprompt list o prev reviewers subscribers
 
     list=
+    prev=""
     if [ "$(git config --bool --get arc.list 2>/dev/null || echo false)" != "false" ]; then
         list=1
     fi
     doprompt=1
-    while getopts lr:s: o; do
+    while getopts lp:r:s: o; do
         case "$o" in
         l)
             list=1
             ;;
+	p)
+	    prev="$OPTARG"
+	    ;;
         r)
             reviewers="$OPTARG"
             ;;
@@ -391,7 +395,6 @@
     fi
 
     save_head
-    prev=""
     for commit in ${commits}; do
         if create_one_review "$commit" "$reviewers" "$subscribers" "$prev" \
                              "$doprompt"; then