diff --git a/diff-sha.sh b/diff-sha.sh
index 13ff18fe..812c105b 100644
--- a/diff-sha.sh
+++ b/diff-sha.sh
@@ -66,7 +66,7 @@ if [[ -z $GITHUB_BASE_REF ]]; then
 
     if [[ -z "$PREVIOUS_SHA" || "$PREVIOUS_SHA" == "0000000000000000000000000000000000000000" ]]; then
       echo "::debug::First commit detected"
-      PREVIOUS_SHA=$(git rev-parse "$(git branch -r --sort=-committerdate | head -1)")
+      PREVIOUS_SHA=$(git rev-parse "$(git branch -r --sort=-committerdate | head -1 | xargs)")
     fi
 
     if [[ "$PREVIOUS_SHA" == "$CURRENT_SHA" ]]; then
diff --git a/get-base-sha.sh b/get-base-sha.sh
index 93bae610..3b6efb02 100644
--- a/get-base-sha.sh
+++ b/get-base-sha.sh
@@ -26,7 +26,7 @@ elif [[ "$INPUT_SINCE_LAST_REMOTE_COMMIT" == "true" ]]; then
 
   if [[ -z "$LAST_REMOTE_COMMIT" || "$LAST_REMOTE_COMMIT" == "0000000000000000000000000000000000000000" ]]; then
     echo "::debug::First commit detected"
-    LAST_REMOTE_COMMIT=$(git rev-parse "$(git branch -r --sort=-committerdate | head -1)")
+    LAST_REMOTE_COMMIT=$(git rev-parse "$(git branch -r --sort=-committerdate | head -1 | xargs)")
   fi
   if [[ "$INPUT_SHA" == "$LAST_REMOTE_COMMIT" ]]; then
     LAST_REMOTE_COMMIT=$(git rev-parse "$INPUT_SHA^1")