Shell for loop: generate a sequence of numbers in Shell

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For loop is one of the most frequently used command in shell. In this post, we show how to generate a sequence of numbers in shell, and use for loop to print out the numbers.

How to generate a range of number in Shell or Bash.  

The answer is using the seq command, here is the seq command syntax:

seq LAST
seq FIRST LAST
seq FIRST INCREMENT LAST

Generate a sequence from 1 to 10

To generate a sequence of numbers from 1 to 10, we can use both seq 10  or seq 1 10

Generate a sequence of numbers from 5 to 10

To generate a sequence of numbers from 5 to 10, we can use seq 5 10 command. 

Generate a sequence of even numbers from 4 to 16

We can use the following command to generate a sequence of even numbers from 4 to 16.

seq 4 2 16

Here, 4 is the start number, 16 is the end number, and 2 is the step

Generate a sequence of even numbers from 20 to 12

The following command can be used to generate a sequence of even number from 20 to 12:

seq 20 -2 12

Use seq command in shell for loop

We can use seq command in shell or bash for loop. See the following example:

Here is the output: