Comparing content of files using Perl

Last Updated : 26 Jul, 2019

In Perl, we can easily compare the content of two files by using the File::Compare module. This module provides a function called compare, which helps in comparing the content of two files specified to it as arguments. If the data present in both the files comes out to be same, the function returns 0 as the output, if the data in the passed files is different, the return value is 1 and if there is any error occurred while accessing the specified/passed files, it returns the value as -1.

Syntax:

use File::Compare;
$compare = compare('FILE_NAME_1', 'FILE_NAME_2');

Note:

Same Content: Return Value [0]

Different Content: Return Value [1]

Error in Accessing Files: Return Value [-1]

Example:

Files Present in the Folder.

When the content of the Files is same:

#!/usr/bin/perl 
print "Content-type: text/html\n\n"; 
  
# Module to use compare function 
use File::Compare; 
  
# compare function to access the passed files. 
$compare = compare("gfg_a.txt", "gfg_c.txt"); 
  
# checking if the files are same 
if ($compare == 0) 
{ 
    print "Files are equal. \n"; 
} 
  
# checking if the files are different 
elsif ($compare == 1) 
{ 
    print "Files are not equal. \n"; 
} 
  
# checking if the file is not accessible 
elsif($compare == -1) 
{ 
    print "Error Occured. \n"; 
} 
  
exit; 

Output:

When the content of the Files is different:

#!/usr/bin/perl 
print "Content-type: text/html\n\n"; 
  
# Module to use compare function 
use File::Compare; 
  
# compare function to access the passed files. 
$compare = compare("gfg_a.txt", "gfg_b.txt"); 
  
# checking if the files are same 
if ($compare == 0) 
{ 
    print "Files are equal. \n"; 
} 
  
# checking if the files are different 
elsif ($compare == 1) 
{ 
    print "Files are not equal. \n"; 
} 
  
# checking if the file is not accessible 
elsif($compare == -1) 
{ 
    print "Error Occured. \n"; 
} 
  
exit; 

Output:

When the file is not accessible:

#!/usr/bin/perl 
print "Content-type: text/html\n\n"; 
  
# Module to use compare function 
use File::Compare; 
  
# compare function to access the passed files. 
$compare = compare("gfg_a.txt", "gfg_d.txt"); 
  
# checking if the files are same 
if ($compare == 0) 
{ 
    print "Files are equal. \n"; 
} 
  
# checking if the files are different 
elsif ($compare == 1) 
{ 
    print "Files are not equal. \n"; 
} 
  
# checking if the file is not accessible 
elsif($compare == -1) 
{ 
    print "Error occurred. The file is not accessible. \n"; 
} 
  
exit; 

Output:

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