Not in answer to your question, (which has been answered) but where you have the block of print statements:

print TOHOST "To: $your_email \nFrom: $your_email\n";
print TOHOST "Subject: Name Change\n";
print TOHOST "$email_send\n";
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You can easily combine those all into one:

print TOHOST "To: $your_email \nFrom: $your_email\n",
     "Subject: Name Change\n", "$email_send\n";
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or if you want to see more clearly what it is sending:

print TOHOST <<EOT;
To: $your_email
From: $your_email
Subject: Name Change
$email_send
EOT
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(as this is an email you're going to need to make sure you have a blank line before the body to seperate it from the header too - but perhaps you already have this in @email before the loop)

Also... you don't seem to be using

use strict;
use warnings;
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In the top of your script... you will do yourself big favours by using them as a matter of habit, because there are a number of errors in your example which they will pick up for you.

You'll also massively aid your debuggging by putting in context relevent info in your error messages including filenames (quoted so you can see if they're empty or have spaces at the end or anything silly) and a short, specific description of what you were trying to do when it died.

Presuming that you have:

$sock, $name, $match, @email, $sendmail, $your_email
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all defined before your example here you might end up with something like:

#!/usr/bin/perl

use strict;
use warnings;

# (the code before your example here...)

my $n = 50;

while (1) {

    my $time = time();
    print $sock "$name\r\n";
    my @output;
    my $output = join( '', @output );
    $| = 1;

    while (<$sock>) {

        if ( $output = /$match/ ) {

            my $searchlog = "searchlog.txt";

            open( FILELOG, ">>$searchlog" )
              || die "Can't write to '$searchlog': $!\n";
            print FILELOG "$time $name\n";
            close FILELOG;

            my $tmpl = "email.txt.asc";
            my @tmpl;

            open( TMPL, $tmpl ) || print "Can't read '$tmpl': $!\n";
            @tmpl = <TMPL>;
            close(TMPL);

            my ( @email_send, $email_send );

            foreach my $line (@tmpl) {
                $line =~ s/XnameX/$name/g;
                push @email, $line;
                $email_send = join( '', @email );
            }

            open( TOHOST, "|$sendmail $your_email" )
              || print "Can't run '$sendmail': $!\n";
            print TOHOST "To: $your_email \nFrom: $your_email\n",
              "Subject: Name Change\n", "$email_send\n";
            close(TOHOST);

        }
        else {

            my $log_txt = "log.txt";
            open( FILELOG, ">>$log_txt" )
              || die "Can't write to '$log_txt': $!\n";
            print FILELOG "$time $name\n";
            close FILELOG;

        }

        sleep( int( 43200 / $n ) - ( time() - $time ) );

    }

}
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