ASDF_ONE {
    magic
    tmp
    tmp
}
ASDF_TWO {
    tmp
    tmp
    tmp
}
string3 {
    tmp
    tmp
    magic
}

##</code><code>##

use warnings;
use strict;

my $file = "/path/to/file.txt";

sub has_word {
    my $arg = $_[0];
    local $/;
    open FILE, '<', $file;

    while ( <FILE> ) {
        if ( m/(ASDF_$arg \{)(.*?)magic(.*?)(\})/s ) {
            close FILE;
            return 1;
        } else {
            close FILE;
            return 0;
        }
    }
}

sub main {
    if (has_word("ONE")) {
        print "ONE already has the word.\n";
    } else {
        print "ONE does not have the word.\n";
    }
    if (has_word("TWO")) {
        print "TWO already has the word.\n";
    } else {
        print "TWO does not have the word.\n";
    }
}

main;

##</code><code>##

ONE already has the word.
TWO already has the word.