There are specific types of variables whose meanings are predefined and have special significance. They perform a specific function as and when required by the programmer. Most of these Perl special variables come with a long English-like naming convention. For example, Operating System Error variable $! which can be written as: $OS_ERROR. All the special variables available within Perl leverage punctuation characters following the usual variable indicator such as at (@), dollar ($), or percent (%) sign, like $_.  For example:   foreach ('Karlos', 'Sue', 'Dee')
{
print($_);
print(" \
");
}