How to Do String Comparison in Batch File?

If you’re one of the many batch script programmers struggling with how to do string comparison in batch file, you’ve come to the correct place and should keep reading 📑 to find the answer.

We’ll explain batch files in this article and show you how to use them. Then we’ll give you a quick rundown of the string, and finally, we’ll describe string comparison in batch file. Furthermore, we will describe how to compare strings using the selection structure, for loop, and the find command. 

So let’s take a deep dive into the article without further ado.

What Is a Batch File and How Can We Use Them?

A plain text file containing a series of commands to be run by the command-line interpreter makes up batch scripting. Although it isn’t frequently used for programming, it isn’t frequently practised, and it isn’t trendy, yet its control and supremacy over the Windows environment must be addressed.

 A quick series of instructions sent into the Windows Command Prompt may perform and carry out almost any activity or action. We can run the batch script by entering commands in the command prompt or executing a batch file.

What Are String and String Interpolation?

A string is typically a sequence of characters in computer programming, either as a literal constant or as a variable. A string in DOS is an organized collection of characters, such as “Zeshan Afridi”. For example, if we want to store the string in a variable, then we write:

Code

myName="Zeshan Afridi"

echo $myName

Output

Zeshan Afridi

In string interpolation, we create a new String value from a combination of constants, variables, literals, and expressions by combining their values inside a string variable.

When performing text interpolation in DOS programming, the set command can be used to align any literals, such as specified numeric variables, on a single line. 

The following example demonstrates how to interpolate a string using numerical values and characters:

Code

@echo off 

SET a=Roll

SET b=Number

SET /A c = 22

SET d=%a% %b% is %c%

echo %d%

pause

Output

Roll Number is 22

Different Ways to do String Comparison in a Batch File

The following are the ways to compare strings in the batch file:

1. Compare string in a Batch file using if structure.
2. Compare string in a Batch file using the if-else structure.
3. Compare string from a file using find.
4. Compare string from a file using findstr.
5. Compare string in a Batch file using for loop.

Method 1: Compare String in Batch File Using If Structure

The logic behind the If statement is such that if the condition becomes true, the If-block is executed; otherwise, the preceding statements in the program.. If two strings are compared in a batch file, the output will display “Strings are equal” on the console screen. 

Now let’s understand this concept with the help of a simple example:

Code

@echo off 

rem Example of if Structure

rem compare two string variables



rem declare and initialize two string variables

SET mystr1=Zeshan 

SET mystr2=Zeshan



rem compare two string variables with the help of == operator

if %mystr1%==%mystr2% echo "Two String variables are equal" 



rem pause the execution at the end of the file

pause

Output

Two String variables are equal

We can also use relational operators(EQU, NEQ) with if Structure to compare two strings. For example

Code

@echo off 

rem Example of if Structure

rem compare two string variables




rem declare and initialize two string variables

SET mystr1=Zeshan 

SET mystr2=Afridi




rem compare two string variables with the help of the EQU operator

if %mystr1% EQU %mystr2% echo "Two String variables are equal" 




rem compare two string variables with the help of NEQ

if %mystr1% NEQ %mystr2% echo "Two String variables are Not equal"




rem pause the execution at the end of the file

pause

Output

Two String variables are Not Equal

Method 2: Compare String in Batch File Using If Else Structure

The If-else conditional structures work such that first, the If block will be executed only if the conditions return true otherwise, the else block will be executed.

Code

@echo off 

rem Example of if else Structure

rem compare two string variables




rem declare and initialize two string variables

SET mystr1=Zeshan 

SET mystr2=Afridi




rem compare two string variables with the help of if else

if %mystr1% == %mystr2% (echo "Two String variables are equal") else (echo "Two String variables are Not equal")




rem pause the execution at the end of the file

pause

Output

Two String variables are Not Equal

Method 3: Compare String From Files Using Find

Find batch command looks for a string in input or files and outputs lines that match. Let’s understand this command with this example:

Text in myfile.txt is:

Zeshan

Afridi

Asim

Amir

Ali

Code

@echo off 

rem Example of find command

rem Look for a string in the text file



FIND "Asim" E:\myfile.txt



pause

Output

Method 4: Compare String from File Using Findstr

You can search for a string in any plaintext file with the findstr command. You can search for a string with this command in a batch file and generate a statement based on the findings.  In the example below, we compare the file strings with the given string and output message if the string is found in the file.

Code

@echo off 

rem Example of findstr command

rem Look for a string in the text file



findstr /m "Zeshan" E:\myfile.txt

if %errorlevel%==0 (

echo String found in File

)



pause

Output

String found in File

Method 5: Compare String in Batch File Using For Loop

To compare strings in a batch file, we can use a loop. Similar to if-else statements, loops are used to change the logic of a programme. Looping generally refers to repeatedly going through something until a condition is met. Only the direct implementation of the for loop is used in batch files. While and do while loops are not present like in other programming languages.

The General syntax of for loop:

FOR %%Loop_var IN set DO statements

Now let’s understand how the loop works with the help of a simple example:

Code

@echo off 

rem Example of for loop

rem Look for a string in the text file




for /f "usebackq tokens=* delims=" %%A in ("e:\myfile.txt") do (

echo %%A

if "%%~A" == "Zeshan" (echo "String match is found") else (echo "String match is not found")

)

pause

Output

Zeshan

"String match is found"

Afridi

"String match is not found"

Asim

"String match is not found"

Amir

"String match is not found"

Ali

"String match is not found"

Press any key to continue . . .

Conclusion

To conclude the article on how to make string comparison in Batch file, we covered five distinct approaches in the article. The selection structure(if and if-else) is the easiest approach to compare two strings in a batch file. 

Additionally, we can use find, findstr, or a for loop to compare strings from files. A for loop is the best way to compare a string to each string in a text file and take action when a match is found.

If you found this article useful, please share it with your fellow programmers and let us know which method worked best for you in the comments section below ⬇️.

Happy programming! 🥳