diff --git a/dev-tools/scripts/prep-solr-ref-guide-rc.sh b/dev-tools/scripts/prep-solr-ref-guide-rc.sh
index 3066f3a2322..305306f55de 100755
--- a/dev-tools/scripts/prep-solr-ref-guide-rc.sh
+++ b/dev-tools/scripts/prep-solr-ref-guide-rc.sh
@@ -36,6 +36,17 @@ if [ $# -lt 2 ] || [ 3 -lt $# ] ; then
     exit 1;
 fi
 
+sha_sum() {
+  if hash sha1sum 2>/dev/null; then
+    sha1sum "$@"
+  elif hash shasum 2>/dev/null; then
+    shasum "$@"
+  else 
+    echo "Can't find sha1sum or shasum, aborting"
+    exit 1;
+  fi
+}
+
 SRC_FILE=$1
 VER_RC=$2
 GPG_ID_ARG=""
@@ -79,6 +90,6 @@ set -x
 mkdir $DIR || exit 1
 mv $SRC_FILE $DIR/$PDF || exit 1
 cd $DIR || exit 1
-sha1sum $PDF > $SHA || exit 1
+sha_sum $PDF > $SHA || exit 1
 gpg $GPG_ID_ARG --armor --output $GPG --detach-sig $PDF|| exit 1