Add traditional for loop bash example to close https://github.com/adambard/learnxinyminutes-docs/pull/654

bash.html.markdown

@@ -8,6 +8,7 @@ contributors:
     - ["Denis Arh", "https://github.com/darh"]
     - ["akirahirose", "https://twitter.com/akirahirose"]
     - ["Anton Strömkvist", "http://lutic.org/"]
+    - ["Rahil Momin", "https://github.com/iamrahil"]
 filename: LearnBash.sh
 ---
 
@@ -140,6 +141,12 @@ do
     echo "$VARIABLE"
 done
 
+# Or write it the "traditional for loop" way:
+for ((a=1; a <= 3; a++))
+do
+    echo $a
+done
+
 # They can also be used to act on files..
 # This will run the command 'cat' on file1 and file2
 for VARIABLE in file1 file2