use strict;
use warnings;

# demonstration of error message
my $test = "";
my $abc = "abc";
if ($abc =~ /xyz/) {       # <- LINE 7
    print "nothing\n";
}
#elsif ($abc =~ /[$test]/) {
if ($abc =~ /[$test]/) {   # <- LINE 11
    print "passed 1st condition\n";
}


##</code><code>##

Unmatched [ before HERE mark in regex m/[ << HERE ]/ at D:\try3.pl line 11.


##</code><code>##

use strict;
use warnings;

# demonstration of error message
my $test = "";
my $abc = "abc";
if ($abc =~ /xyz/) {    # <- LINE 7
    print "nothing\n";
}
elsif ($abc =~ /[$test]/) {
#if ($abc =~ /[$test]/) {   # <- LINE 11
    print "passed 1st condition\n";
}


##</code><code>##

Unmatched [ before HERE mark in regex m/[ << HERE ]/ at D:\try3.pl line 7.