This is a FAQ (see perlfaq4): 
perldoc -q count

[download]
use warnings;
use strict;

my $str = "thisthis";
if ( my $n = () = ($str =~ m/this/g) ) {
    print qq{Found $n occurrence(s) of "this"\n};
}

__END__

Found 2 occurrence(s) of "this"

[download]
Perl Idioms Explained - my $count = () = /.../g

In reply to Re: Count number of occurrences of a substr by toolic
in thread Count number of occurrences of a substr by Jerbear217

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