run.sh: complain if not passed width/height

diff --git a/run.sh b/run.sh
index a5cb085..205d5fd 100755 (executable)
--- a/run.sh
+++ b/run.sh
@@ -1,5 +1,9 @@
 #!/bin/bash
 
 # run from source directory
+if [ -z "$1" -o -z "$2" ]; then
+       echo "USAGE: $0 \$COLUMNS \$LINES" >&2
+       exit 1
+fi
 
 script -f >(coffee server.coffee "$@" >log.txt 2>&1)