=over =item oct EXPR =item oct Interprets EXPR as an octal string and returns the corresponding value. (If EXPR happens to start off with C<0x>, interprets it as a hex string. If EXPR starts off with C<0b>, it is interpreted as a binary string. Leading whitespace is ignored in all three cases.) The following will handle decimal, binary, octal, and hex in the standard Perl or C notation: $val = oct($val) if $val =~ /^0/; If EXPR is omitted, uses C<$_>. To go the other way (produce a number in octal), use sprintf() or printf(): $perms = (stat("filename"))[2] & 07777; $oct_perms = sprintf "%lo", $perms; The oct() function is commonly used when a string such as C<644> needs to be converted into a file mode, for example. (Although perl will automatically convert strings into numbers as needed, this automatic conversion assumes base 10.) =back