Perl only understands octal and hex numbers as such when they occur as literals in your program. Octal literals in perl must start with a leading "0" and hexadecimal literals must start with a leading "0x". If they are read in from somewhere and assigned, no automatic conversion takes place. You must explicitly use oct() or hex() if you want the values converted to decimal. oct() interprets both hex ("0x350") numbers and octal ones ("0350" or even without the leading "0", like "377"), while hex() only converts hexadecimal ones, with or without a leading "0x", like "0x255", "3A", "ff", or "deadbeef". The inverse mapping from decimal to octal can be done with either the "%o" or "%O" sprintf() formats. To get from decimal to hex try either the "%x" or the "%X" formats to sprintf().
This problem shows up most often when people try using chmod(), mkdir(), umask(), or sysopen(), which by widespread tradition typically take permissions in octal.
chmod(644, $file); # WRONG
chmod(0644, $file); # rightNote the mistake in the first line was specifying the decimal literal
644, rather than the intended octal literal 0644. The problem can
be seen with:
printf("%#o",644); # prints 01204Surely you had not intended chmod(01204, $file); - did you? If you
want to use numeric literals as arguments to chmod() et al. then please
try to express them as octal constants, that is with a leading zero and
with the following digits restricted to the set 0..7.