hex

hex
Interprets EXPR as a hex string and returns the corresponding numeric value. If EXPR is omitted, uses $_ .
```
    print hex '0xAf'; # prints '175'
    print hex 'aF';   # same
    $valid_input =~ /\A(?:0?[xX])?(?:_?[0-9a-fA-F])*\z/
```
A hex string consists of hex digits and an optional 0x or x prefix. Each hex digit may be preceded by a single underscore, which will be ignored. Any other character triggers a warning and causes the rest of the string to be ignored (even leading whitespace, unlike oct). Only integers can be represented, and integer overflow triggers a warning.

To convert strings that might start with any of , 0x , or 0b, see oct. To present something as hex, look into printf, sprintf, and unpack.