Deal with shellcheck in 1998/df/try.sh

1998/df/try.sh

@@ -15,7 +15,7 @@ make CC="$CC" all >/dev/null || exit 1
 # clear screen after compilation so that only the entry is shown
 clear
 
-while [[ 1 ]]; do
+while :; do
     read -r -n 1 -p "Press any key to run ./df or 'q' to quit: "
     echo 1>&2
     if [[ "$REPLY" = "q" || "$REPLY" = "Q" ]]; then