bugfix: verify BOOKI_FILE variable is not empty

1 files changed, 1 insertions, 1 deletions

diff --git a/booki.c b/booki.c
index 682f333..1738f9f 100644
--- a/booki.c
+++ b/booki.c
@@ -1050,7 +1050,7 @@ void help(bool err) {
 /*** the main event ***/
 int main(int argc, char* argv[]) {
     char* booki_file = getenv("BOOKI_FILE");
-    if (!booki_file) {
+    if (!booki_file || strlen(booki_file) == 0) {
         printf("expecting BOOKI_FILE variable\n");
         return 1;
     }