Ultrix-11

On Wed, Aug 25, 2021 at 12:04:34PM -0400, Douglas Taylor via cctalk wrote: [...] Terminal styling control codes are hit-and-miss even when exclusively using modern tools. These days, I pretty much exclusively use iTerm2 as my terminal emulator, which has a bewildering array of compatibility-tweaking controls to fiddle with, because everything seems to interpret the alleged standards differently. When I was relatively new to Linux I just put teminal oddities down to me not knowing what I was doing and configuring it wrong, but then had the opportunity to connect a real VT100 to it. "export TERM=vt100" is all that's needed, right? There were *loads* of rendering errors, and I got my first lesson into how well-tested Linux's termcap/terminfo database was. Fast-forward a quarter-century and our terminal emulators are expected to handle Unicode, which brings variable-width characters to our fixed-grid terminal emulators, yet not break too badly if the endpoint is not Unicode-aware and sends something like Latin-1 instead. Bold and so on are set via SGR ("Select Graphic Rendition") sequences, and Wikipedia gives a summary at <https://en.wikipedia.org/wiki/ANSI_escape_code#SGR_(Select_Graphic_Rendition)_parameters>. Here's a quick bash one-liner to display them on your terminal: for i in $(seq 1 127) ; do printf '\033[%dm SGR %d \033[0m\n' $i $i ; done (Progressively reduce that 127 if your terminal doesn't have scrollback and you can't see the earlier entries.) My *terminal* (i.e. iTerm2) supports 1-5, 7, 9, 30-39, 40-49, 90-97 and 100-107, i.e. bold, dim, italic, underline, blink, inverse, strikethrough, and all of the colours. However, a lot of useful software includes its own nested terminal emulator, and support is less good: connecting to a remote server using mosh(1) loses dim and strikethrough; tmux(1) turns italic into inverse, except on FreeBSD where it also loses dim, blink and strikethrough and mysteriously gives me another underline at 21 (probably due to it knowing about double-underline, but doing a substitution for the benefit of my terminal which doesn't). And if I use "watch -dc" to run a command repeatedly and highlight the changes, it only supports the 8 basic colours. If you test your own systems you may well come up with different results, because this nested emulation relies on termcap/terminfo databases knowing about the full capabilities of your terminal (MacOS doesn't include sitm/ritm for italic, for example) and TERM being set correctly at each level of nesting, so good luck with that.