move shell scripts and zsh and add fav vscode themes

shell/shell_scripts/lessons/factorial.sh

@@ -0,0 +1,18 @@
+#! /bin/bash
+
+n=0
+on=0
+fact=1
+
+echo -n "Enter number to find factorial : "
+read n
+
+on=$n
+
+while [ $n -ge  1 ]
+do
+  fact=`expr $fact \* $n`
+  n=`expr $n - 1`
+done
+
+echo "Factorial for $on is $fact"