test for syntax errors

.githooks/post-checkout

@@ -1,3 +1,4 @@
+#!/bin/bash -
 # echo "POST-CHECKOUT"
 # echo "PREV-HEAD=$1"
 # echo "CURR-HEAD=$2"
@@ -25,9 +26,7 @@ if [ -f $CHECKOUT_HISTORY_FILE ]; then
         echo "DOWNLOAD, /etc/psa_config/DC2C_print04.json, $now, N/A" >> $GIT_UPDATE_LOG
         echo "DOWNLOAD, /etc/psa_config/DC2C_print29.json, $now, N/A" >> $GIT_UPDATE_LOG
         echo "DOWNLOAD, /etc/psa_config/DC2C_print32.json, $now, N/A" >> $GIT_UPDATE_LOG
-        if [ $(wc -l < "$OPKG_COMMANDS_FILE") -gt 0 ]; then
-            # file not empty
-            # mark opkg_commdands to be executed by update-tool.
+        if grep -q . "${OPKG_COMMANDS_FILE}"; then
             readarray opkg_commands < <(cat $OPKG_COMMANDS_FILE)
             for opkg_c in "${opkg_commands[@]}"; do
                 test -z $opkg_c && continue;