Show help message when using `hexyl` with no argument. about hexyl

[sharkdp]

Thank you for the feedback.

In this case, hexyl is waiting for input from stdin. This is intended in order to allow users to pipe output into hexyl, i.e.

tail -c 1024 some-file | hexyl

[ErichDonGubler]

It seems like it'd be pretty rare for somebody to be typing in a hex dump by hand. Maybe printing a warning to stderr would be appropriate if a TTY is detected?

[sharkdp]

It seems like it'd be pretty rare for somebody to be typing in a hex dump by hand. Maybe printing a warning to stderr would be appropriate if a TTY is detected?

That's probably correct and interactive TTY detection on STDIN would be a way to fix this, yes. Are there any other tools that do something like this, i.e. disable input from STDIN if its from a terminal? hexdump, xxd and all other Unix tools I can think of do not have this behavior.

[ErichDonGubler]

@sharkdp: I don't even necessarily know about disabling input if you print a warning, but that's an interesting idea. AFAIK, Unix is the only set of common terminal tools that deal with hex dumps. Windows' Powershell has Format-Hex, but it's fairly hard to get it to use stdin directly anyway.

[sharkdp]

I think I'd like to just keep this as is. Maybe someone wants to copy & paste some data into the terminal. For example, copy & paste a Unicode string to see its UTF-8 representation with hexyl.

Let me know if somebody has strong opinions on this, so I can reopen the ticket.

[kilobyte]

+1 — the old Unix design guideline for command-line tools was/is "no news is good news".