[release-18.0] Update env.sh so that is does not error when running o…

…n Mac (#15835) (#15914)

Signed-off-by: bddicken <bddicken@gmail.com>
Co-authored-by: vitess-bot[bot] <108069721+vitess-bot[bot]@users.noreply.github.com>

examples/common/env.sh

@@ -79,6 +79,8 @@ mkdir -p "${VTDATAROOT}/tmp"
 alias mysql="command mysql --no-defaults -h 127.0.0.1 -P 15306"
 alias vtctldclient="command vtctldclient --server localhost:15999"
 
-# Make sure aliases are expanded in non-interactive shell
-shopt -s expand_aliases
+# If using bash, make sure aliases are expanded in non-interactive shell
+if [[ -n ${BASH} ]]; then
+    shopt -s expand_aliases
+fi