diff --git a/release-tool b/release-tool
index 11fdf501..be6bbc7a 100755
--- a/release-tool
+++ b/release-tool
@@ -246,7 +246,7 @@ checkTransifexCommandExists() {
 
 # re-implement realpath for OS X (thanks mschrag)
 # https://superuser.com/questions/205127/how-to-retrieve-the-absolute-path-of-an-arbitrary-file-from-the-os-x
-if [ "$(uname -s)" == "Darwin" ]; then
+if $(command -v realpath > /dev/null); then
     realpath() {
         pushd . > /dev/null
         if [ -d "$1" ]; then