diff --git a/install.sh b/install.sh
index 79fd5dc..8a413a9 100755
--- a/install.sh
+++ b/install.sh
@@ -3,7 +3,7 @@
 set -euo pipefail
 
 cols=80
-if [ "$TERM" != "dumb" ]
+if [ -n "$TERM" ] && [ "$TERM" != "dumb" ]
 then
   cols=$(tput cols)
 fi