Question

an easy example for FOR Loops?

Answer 1

A FOR loop is very similar to a WHILE loop in that it continues to process a block of code until a statement becomes false, however everything is defined in a single line. The basic structure for a FOR loop is:

for ( start; conditional; increment) { code to execute; }

Let's go back to our first example using the WHILE loop, where we printed out the numbers 1 through 10 and do the same thing using a FOR loop.

 <?php
 for ($num=1; $num <= 10; $num++ )
     {
     print $num . " ";
     }
 ?>

The FOR loop can also be used in conjunction with a conditional, just like we did with the WHILE loop:

 <?php
 for ($num=1; $num <= 10; $num++ )
     {
     if ($num < 5)
         {
         print $num . " is less than 5 <br>";
         }
     else
         {
         print $num . " is not less than 5 <br>";
         }   
     }
 ?>

Answer 2

How do I use bash for loop to repeat certain task under Linux / UNIX operating system? How do I set infinite loops using for statement? How do I use three-parameter for loop control expression?

A 'for loop' is a bash programming language statement which allows code to be repeatedly executed. A for loop is classified as an iteration statement i.e. it is the repetition of a process within a bash script.

For example, you can run UNIX command or task 5 times or read and process list of files using a for loop. A for loop can be used at a shell prompt or within a shell script itself.