=over =item $] X<$]> See L for a more modern representation of the Perl version that allows accurate string comparisons. 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: warn "No PerlIO!\n" if $] lt '5.008'; The floating point representation can sometimes lead to inaccurate numeric comparisons, so string comparisons are recommended. See also the documentation of C and C for a convenient way to fail if the running Perl interpreter is too old. Mnemonic: Is this version of perl in the right bracket? =back