=over

=item $]

The version + patchlevel / 1000 of the Perl interpreter.  This variable
can be used to determine whether the Perl interpreter executing a
script is in the right range of versions.  (Mnemonic: Is this version
of perl in the right bracket?)  Example:

    warn "No checksumming!\n" if $] < 3.019;

See also the documentation of C<use VERSION> and C<require VERSION>
for a convenient way to fail if the running Perl interpreter is too old.

The use of this variable is deprecated.  The floating point representation
can sometimes lead to inaccurate numeric comparisons.  See C<$^V> for a
more modern representation of the Perl version that allows accurate string
comparisons.

=back