Comparing content of files using Perl

Last Updated : 06 Jun, 2022

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:

Perl

#!/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 Occurred. \n";
}
 
exit;

Output:

When the content of the Files is different:

Perl

#!/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 Occurred. \n";
}
 
exit;

Output:

When the file is not accessible:

Perl

#!/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;