# Searching For Hex Digits If you want to find sequences of hex digits (`A-F`, `a-f` and `0-9`) in a search, you can hack together something like: ``` /[A-Fa-f0-9]\+ ``` This is a bit verbose, though. Vim has a number of built in character classes that can be referenced in searches and substitutions. For hex digits, there is `\x`. Using this, the search above can be achieved with: ``` /\x\+ ``` See `:h \x` for more details and other character classes.