hex EXPR
hex

Interprets EXPR as a hex string and returns the corresponding value. (To convert strings that might start with either 0, 0x, or 0b, see "oct".) If EXPR is omitted, uses $_.

print hex '0xAf'; # prints '175'
print hex 'aF';   # same

Hex strings may only represent integers. Strings that would cause integer overflow trigger a warning. Leading whitespace is not stripped, unlike oct(). To present something as hex, look into "printf", "sprintf", and "unpack".