Basics of Batch Scripting
Batch Scripting consists of a series of commands to be executed by the command-line interpreter, stored in a plain text file. It is not commonly used as a programming language and so it is not commonly practiced and is not trending but its control and dominance in the Windows environment can never be neglected. Almost every task and every action can be performed and executed by a simple sequence of commands typed on the Windows Command Prompt.
Batch Script execution
There are 2 ways to execute a batch script.
- Type the batch script in the command prompt.
- Write the code of script in a file and execute it through the command prompt.
Typing commands again and again on the terminal can be a very tedious task to do if we have a very lengthy code. So option 2 is generally preferred to create batch files.
Creating Batch Files
Steps to create a Batch file are pretty simple:-
- Create a new text file with a ‘.txt‘ extension.
- Now rename this file with extension as ‘.bat‘ this creates a Batch file.
- Now open this .bat file in any text editor and start scripting.
To begin scripting we must be aware of the commands of the batch interface. The commands of Batch are sometimes similar to Linux Scripting commands.
Basic batch commands are all case insensitive and can be used to perform a specific set of instructions:-
- DIR – The ‘dir’ command is used to get all the directories, sub-directories, and files present in the current working directory.
- CD – The ‘cd’ command is used to change the current working directory.
- VER – The ‘ver’ command tells the version of the user’s Windows.
- CLS – The ‘cls’ command is used to clear the screen of the command prompt.
- ECHO – The ‘echo’ command is by default ‘on’ but if we turn it off by ‘echo off’ it turns off prompt till the time ‘echo on’ is passed.
- @ – The ‘@’ if used before any command hides which command is running.
- @ECHO OFF – This commands serves as the start point to any basic batch script as it hides the prompt with ‘echo off’ and hides ‘echo off’ command with ‘@’.
- HELP – This command tells us all about the commands available in the cmd. It runs only if the cmd is run as an administrator.
Data Types in Batch
- Integers – Batch supports the whole set of positive and negative integers
- Strings – Unlike most programming languages we rarely use (“”) double-quotes here but we use ‘echo‘ command to print strings
Note: Batch doesn’t support floating-point values i.e. values with precision.
Variables in Batch Scripting
A variable is an entity that stores a specific value and allows the user to perform any set of instructions on it. To create variables we use the command “SET” command. A variable, unlike many programming languages, can be assigned simply without specifying any data type to it.
SET my_variable=Hello World
To print this variable we need to use the command ECHO but with a slight variation. Since echo prints both strings and variables to print string we simply write the string after ECHO as
ECHO Hello World
But to print a variable we use ECHO in a different way bypassing the variable names inside two percent signs (%) so that variable name doesn’t become a string-
Working with Batch Scripts
Creating our own Batch Scripts
Example 1: To print “GeeksForGeeks” on the command prompt with and without using a variable.
Without using a variable
With a variable
SET my_var=GeeksForGeeks ECHO %my_var%
Arithmetic Operators in a Batch Script
List of operators :
SET /A sum=1+1 ::addition operator ECHO %sum% SET /A mul=7*9 ::multiplication operator ECHO %mul% SET /A div=9/3 ::Division operator ECHO %div% SET /A assign=10 ::Assignment operator ECHO %assign% SET /A assign+=15 ::Increment then assignment operator ECHO %assign% SET /A mod= 10%3 ::Modulus/Remainder operator ECHO %mod%