--- layout: page category-page: scripts category-title: Scripting tags: loop for done script scripting author: Matteo Omenetti title: For Loop ---

The second type of loops are for loops. They follow this sintax:

  for [variable] in [list] do
    [code]
  done

Their purpose is to iterate over a list. Also while loops could do this, you might argue...
Of course they could, but for loops are specifically meant to do this. Therefore, for instance, you don't have to decleare your counter variable outside the loop. Most importantly, this variable can be accessed from inside the loop.

For loops take this form:

for VARIABLE in 1 2 3 4 5 .. N
do
	command1
	command2
	commandN
done

Here is a simple example:

for i in 1 2 3 4 5
do
   echo "Welcome $i times"
done

This first example of code simply displays a welcome message 5 times. The output of this piece of code is:

Welcome 1 times
Welcome 2 times
Welcome 3 times
Welcome 4 times
Welcome 5 times

There are also other ways to specify the numerical range . For instance, if your numerical range is too big, you can simply write: {1..100} . This piece of code means every natural number between 1 and 100 (both included).
Ranges can also count backward like this: {10..1}. You can even icrement the numerical value by step of two: {0..10..2} . This piece of code means every natural number between 0 and 10 with a step of two, 0 2 4 6... 10.