Perl script to open a file and read a string

Question

I know how to open a file and display entire content using perl script, but how can i read a string from file into a variable

Following is to open file and display entire content

#!/usr/bin/perl 
use strict;
use warnings;

my $filename = '/home/abc/data.txt';
if (open(my $fh, '<', $filename)) {
  while (my $row = <$fh>) {
    chomp $row;
    print "$row\n";
  }
} else {
  warn "Could not open file '$filename' $!";
}

My requirement is

   #!/usr/bin/perl 
    use strict;
    use warnings;

    my $filename = '/home/abc/data.txt';
    my $foo = ""
    if (open(my $fh, '<', $filename)) {
     ---- Read test_reg_ip string from data.txt into variable 
         $foo=test_reg_ip;
    } else {
      warn "Could not open file '$filename' $!";
    }
    print "$foo\n";

Following is the input file data.txt

#############################################################################################
# mon_server_ip
# This parameter value should point to the IP address where the mon Server
# is installed
#############################################################################################
mon_server_ip = 127.0.0.1

#############################################################################################
# test_reg_ip
# This parameter value should point to the IP address where reg server is
# installed
#############################################################################################
test_reg_ip = 127.0.0.1

#############################################################################################
# mon_port
# This parameter value should point to the mon port 
#############################################################################################

Chankey Pathak · Accepted Answer · 2015-09-10 12:10:02Z

3

use strict;
use warnings;
open (my $fh, "<", "file.txt") or die $!;
while(<$fh>){
    if ($_ = /test_reg_ip = (.*)/){
        my $ip = $1;
        print "IP is $ip\n";
    }
}

answered Sep 10, 2015 at 12:10

Chankey Pathak

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Comments

stevieb · Accepted Answer · 2015-09-10 13:03:11Z

2

This code assumes a few things, but if the config entries are consistently the same, you could iterate the entire file and store all the config details in a hash in case you need more of them later:

use warnings;
use strict;

open my $fh, '<', 'in.txt'
  or die $!;

my %data;

while (<$fh>){
    if (/^(\w+)\s*=\s*(.*)$/){
        $data{$1} = $2;
    }
}

print "$data{test_reg_ip}\n";

print "$data{mon_server_ip}\n";

edited Sep 10, 2015 at 13:03

answered Sep 10, 2015 at 12:40

stevieb

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Comments

José Trindade · Accepted Answer · 2015-09-10 12:12:30Z

1

you need a regexp. try something like this:

if ($row =~ /test_reg_ip\s=\s(\d{1,3}\.\d{1,3}.\d{1,3}.\d{1,3})/) {
   my  $foo = $1; # your IP goes here, on the first (and only matched group)
}

answered Sep 10, 2015 at 12:12

José Trindade

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