I usually turn to Google to find information about a Unix command or function. But there’s a faster and easier way to find what you’re looking for: apropos(1).

If you are looking for a way to turn a string into hexadecimal numbers:

$ apropos hex
ascii (7) - octal, hexadecimal and decimal ASCII character sets
hexdump (1) - ascii, decimal, hexadecimal, octal dump
od (1) - octal, decimal, hex, ascii dump
xxd (1) - make a hexdump or do the reverse.