$ perl -E 'say oct "0x47"; say hex "0x47"'
71
71

##</code><code>##

$ perl -E 'say "0x47_not_hex" =~ /^0x/ ? "is hex" : "is NOT hex"'
is hex
$ perl -E 'say "0x47_not_hex" =~ /^0x[0-9a-fA-F]+$/ ? "is hex" : "is NOT hex"'
is NOT hex