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#MAC OS BASH SHELL SCRIPT FOR LOOP FILES IN DIRECTORY HOW TO#
#MAC OS BASH SHELL SCRIPT FOR LOOP FILES IN DIRECTORY FOR MAC#

The technique to pass Bash script arguments via the command line.Īlso, sometimes you might have the need to delay some of the commands executed in your while loops.How an index variable can be used in a while loop.The way you can use the arithmetic operator to calculate the remainder of a division.

#MAC OS BASH SHELL SCRIPT FOR LOOP FILES IN DIRECTORY HOW TO#

How to use an if statement nested in a while loop.

There are other ways to implement a loop in Bash, see how you can write a for loop in Bash. The script works well, so our changes are correct 🙂 It’s the variable that in Bash contains the first argument passed to a script.Įxecute the script again, this time passing N via the command line.

Replace 20 with N in the condition of the while loop #!/bin/bash.

Use a variable called N and assign to it the first argument passed to the script.

To do that we will have to apply the following changes: We now want to pass N via the command line. Passing N as an Argument Through the Command Line The Bash script does print the odd numbers from 1 to 20. Note: Arithmetic operations can be executed in a Bash script using $(( )).

Increment the value of INDEX by 1 before executing the next iteration of the while loop.

Check if the REMAINDER is not zero…in that case print INDEX because it’s an odd number.

At every iteration of the loop calculate the REMAINDER for the division of the INDEX by 2.

Start a while loop that is executed if the value of INDEX is less than 20.

Set the value of the variable INDEX to 0.

How does this apply to this specific case? Print Odd Numbers Using a Bash Script INDEX=0Īnd if we translate this logic into an actual Bash script… #!/bin/bash This applies to any Bash shell running on Unix-like systems (including MacOS).įirst of all let’s have a look at the generic structure of a while loop in Bash: while Īs long as the condition between square brackets is true the commands between do and done are executed. You will see how our script looks like if we hardcode the value of N in it, and then you will learn how to pass the value of N to the script as an argument via the Linux command line. You can also automate shell scripts using tools such as launchd or Apple Remote Desktop.

#MAC OS BASH SHELL SCRIPT FOR LOOP FILES IN DIRECTORY FOR MAC#

Let’s create a loop that goes through N numbers and prints only the odd ones. Why for mac bash script Shell scripts are useful because you can combine many common tasks into one script, saving you time and possible errors when performing similar tasks over and over.