How can I count the number of occurrences of a substring within a string?

    $string = "ThisXlineXhasXsomeXx'sXinXit":
    $count = ($string =~ tr/X//);
    print "There are $count X charcters in the string";

This is fine if you are just looking for a single character. However, if you are trying to count multiple character substrings within a larger string, tr/// won't work. What you can do is wrap a while() loop around a global pattern match. For example, let's count negative integers:

    $string = "-9 55 48 -2 23 -76 4 14 -44";
    while ($string =~ /-\d+/g) { $count++ }
    print "There are $count negative numbers in the string";