undefined | Better HN

0 pointsarp2424y ago0 comments

The standard is ECMA-48; for example this 1991 version[1] lists all the SGR codes to colour stuff (page 61), the cursor movement codes, etc. The 1991 is just the first version that came up, I believe some of this goes back to the late 70s.

Terminfo goes back to the early 80s, during the time of the Great Unix Wars when everyone was doing everything different for the fun and sake of it. It contains a lot of cruft. People are mentioning ADM-3A terminals here and that's all very nice, but these are machines from the 70s. No one is using them, except some people for the fun/historical value. Do people write software to be compatible with Bell Labs Unix from 1976 or 1BSD that Bill Joy was working on? Of course not.

AFAIK there are very few modern terminals (or rather, terminal emulators) that don't support that basic set of escape codes. I can't really find any in a quick glance at my system's terminfo database.

For basic operations it's pretty safe to rely on, at least if you care about Unix only (not entirely sure about Windows, I believe it's all different there). Once you go beyond that it gets a bit more iffy.

There are loads of programs that hard-code these things, including very popular once. The issue trackers of these projects are not getting filled with people reporting garbled output.

[1]: https://www.ecma-international.org/wp-content/uploads/ECMA-4...

0 comments

2 comments · 1 top-level

junon4y ago· 1 in thread

ECMA-48 was what I was referring to, thanks. And no, I'm not convinced it was the standard many were conforming to. Perhaps Xterm, but not everyone.

Further ECMA and ANSI are two separate standards bodies. While ECMA-48 is listed as one of the standards on the Wikipedia page I've yet to find anything that claims to conform to that standard. The same with the other listed "standards".

arp242OP4y ago

Actually that Wikipedia page lists the history of standards:

"The ANSI standard attempted to address these problems by making a command set that all terminals would use and requiring all numeric information to be transmitted as ASCII numbers. The first standard in the series was ECMA-48, adopted in 1976. It was a continuation of a series of character coding standards, the first one being ECMA-6 from 1965, a 7-bit standard from which ISO 646 originates. The name "ANSI escape sequence" dates from 1979 when ANSI adopted ANSI X3.64. The ANSI X3L2 committee collaborated with the ECMA committee TC 1 to produce nearly identical standards. These two standards were merged into an international standard, ISO 6429. In 1994, ANSI withdrew its standard in favor of the international standard."

So ANSI X3.64 was the original, but things has since converged and it has been superseded by the ECMA/ISO one.

The document that many people use is probably the Xterm ctlseqs page, which is just the same as the ECMA codes with additional notes, extensions, etc. So I suppose that's the de-facto standard now.

j / k navigate · click thread line to collapse