use strict;
use warnings;

my $testFileName = 'testFile.txt';
my $tempFileName = 'delme.txt';

# Create a sample file
open my $out, '>', $testFileName or die "Failed to create $testFileName: $!";

print $out <<END_STR;
be_address = remote_be_address
be_address1 = remote_be_address
be_address2 = remote_be_address
END_STR

close $out;

# The 'meat'
open my $in, '<', $testFileName;
open $out, '>', $tempFileName or die "Failed to create $tempFileName: $!";

while (<$in>) {
    s/remote_be_address/192.168.106.60/g;
    print $out $_;
}

close $in or die "Failed to close $testFileName: $!";
close $out or die "Failed to close $tempFileName: $!";

unlink $testFileName;
rename $tempFileName, $testFileName;

# Show the result
open $in, '<', $testFileName;
print <$in>;
close $in or die "Failed to close $testFileName: $!";