diff --git a/install.sh b/install.sh
index 9588847d01..0213a0c4ac 100755
--- a/install.sh
+++ b/install.sh
@@ -422,11 +422,9 @@ pstree() {
     for pid in $@; do
         echo $pid
         # Find and show pstree for child processes of $pid
-        while read parent child; do
+        $(ps -o ppid= -o pid=) | while read parent child; do
             [ $parent -ne $pid ] || pstree $child
-        done <<-EOF
-            $(ps -o ppid= -o pid=)
-EOF;
+        done
     done
 }