diff --git a/tools/install/create_lazarus_deb.sh b/tools/install/create_lazarus_deb.sh
index 8c0e9f4ff4..a64c110c44 100755
--- a/tools/install/create_lazarus_deb.sh
+++ b/tools/install/create_lazarus_deb.sh
@@ -163,7 +163,7 @@ if [ "$UseCHMHelp" = "1" ]; then
   cp -v *.kwd *.chm $LazDestDir/docs/chm/
   cd -
 fi
-if [ -n $Pas2jsZip ]; then
+if [ ! "x$Pas2jsZip" = "x" ]; then
   # unzip pas2jszip to pas2js/version
   mkdir $LazDestDir/pas2js   # fails if already there -> good
   unzip $Pas2jsZip -d $LazDestDir/pas2js