`vis`: display non-printable characters in a visual format
`cat -e`: Display non-printing characters and display a dollar sign (`$') at the end of each line.
`hexdump -c`: Display the input offset in hexadecimal, followed by sixteen space-separated, three column, space-filled, characters of input data per line.
`od -a`: Output named characters.
Or `cat -v`, the namesake of http://cat-v.org/. :P
It really is a treasure. Take the time to browse, it's well worth it if you're somewhat interested in unix history and not overly familiar with the subject already.
(They give off rays or something ... took a cursory look to see if I was being unfair, and booom - https://www.gkayaalp.com/blog/20170206_emacs-argument.html )
TBH I do actually like Unix and Plan9, but having read a big part of cat-v website in the past, most of the views there are fanatical, and are more bitter, cynical and disingenuous than I can ever force myself to be. Especially the way incredibly useful and important OSS projects are denigrated and misrepresented is really annoying (see the harmful stuff section, for example).
One part is a matter of taste, and having been around both styles, I like better the 'keep it simple' approach. Too many functions/options overload my simple brain ;-)
I'll also add my favorite companion to `od` and hexdumps: `man ascii`.
P.S. May we please have a basic Markdown parser for HN?
$ apt-cache show xxd | grep Source:
Source: vim (2:8.0.1453-1)
Source: vim