I work a lot with network and serial communications software, so it is often necessary for me to have code to display or log hex dumps of data packets.
Every time I
The unix tool xxd is distributed as part of vim, and according to http://www.vmunix.com/vim/util.html#xxd, the source for xxd is ftp://ftp.uni-erlangen.de:21/pub/utilities/etc/xxd-1.10.tar.gz. It was written in C and is about 721 lines. The only licensing information given for it is this:
* Distribute freely and credit me,
* make money and share with me,
* lose money and don't ask me.
The unix tool hexdump is available from http://gd.tuwien.ac.at/softeng/Aegis/hexdump.html. It was written in C and can be compiled from source. It's quite a bit bigger than xxd, and is distributed under the GPL.