diff --git a/demo/quick_start/preprocess.sh b/demo/quick_start/preprocess.sh
index 58a72147c5e41351634395e770e9a214ed3cb01d..c9190e2dd2ef754bf3c7287006322b52493dc3a0 100755
--- a/demo/quick_start/preprocess.sh
+++ b/demo/quick_start/preprocess.sh
@@ -23,7 +23,7 @@ set -e
 export LC_ALL=C
 UNAME_STR=`uname`
 
-if [[ ${UNAME_STR} == 'Linux' ]]; then
+if [ ${UNAME_STR} == 'Linux' ]; then
   SHUF_PROG='shuf'
 else
   SHUF_PROG='gshuf'