diff --git a/run_tb.sh b/run_tb.sh
index ff51edd..0ccc2f0 100755
--- a/run_tb.sh
+++ b/run_tb.sh
@@ -64,7 +64,7 @@ execute_tcl() {
 
     # Convert TCL 'set VAR value' to bash 'VAR=value'
     {
-        grep -E '^set [A-Z_]+ ' "$tcl_file" | while read -r _ var value; do
+        grep -E '^set [A-Z0-9_]+ ' "$tcl_file" | while read -r _ var value; do
             echo "${var}=${value}"
         done