Diff of 2 files using perl

Shell Programming and Scripting
1

Assitance needed in checking file difference using a perl script

Below is the example

I wanted a report saying file2 has an update of new value.

File1 old date

Alpha    156
Beta     255
Gama    6987
segma   4578

File2 new date

Alpha    156
Beta     255
Gama    1000
segma   4578

Result
File2 has an update

Gama 1000
2

Here is a solution using awk program:

awk 'NR==FNR{A[$1]=$2;next}$1 in A&&$2!=A[$1]' file1 file2

Disregard if you are looking for a perl solution.

3

I have a perl script so i want to add the below step in perl .

4

Use hashes %_1 and %_2 with their members. Fill %_3. Report from %_3.

use strict ;

my $infile1 = q[File1];
my $infile2 = q[File2];
my %_1 = () ;
my %_2 = () ;
my %_3 = () ;

#now firstfill...

open (I, '<' . $infile1) or die @! ;
open (II, '<' . $infile2) or die @! ;

while (<I>) {
 chomp ;
 m/^(.+?)\s+([0-9\+\-]+)$/ ;
 $_1{$1} = $2 ;
 m/./; #reset regex
}

while (<II>) {
 m/./ ; #reset regex
 chomp ;
 m/^(.+?)\s+([0-9\+\-]+)$/ ;
 $_2{$1} = $2 ;
}

#fill....

push %_3, map { ($_, $_2{$_}) } grep { $_1{$_} != $_2{$_} } keys %_2 ; 

#now report ...

print qq[\n], $_, qq[\t\t], $_3{$_} for sort keys %_3 ;