[zadjii]

From my experience, the colon separator for 256/rgb attributes is a fairly recent clarification to the spec. I think that's the way it was always supposed to be. But when I was initially writing the 256 color support for the Windows Console about 6 years ago, `TERM=xterm-256color` still emitted colors with just the semicolons as a separator.

The colons are more correct, but the semicolons are seemingly more broadly supported.

[wezfurlong]

I don't recall where I saw it, but my understanding was that : was in the original spec but one of the early implementors (Konsole?) misread it and used ; and that erroneous form is what took off, and here we are today.

[follower]

I'm guessing it may have been one or both of these `xterm`-related documents:

* <https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h4-F...>

* <https://invisible-island.net/xterm/xterm.faq.html#color_by_n...>

More details in my other comment: https://news.ycombinator.com/item?id=35157058

[drougge]

Part of the problem is probably that termcap uses : as a separator between capabilities. There is \C for colon, but there are implementations that don't support it. If nothing else I know the termcap[info] command in screen doesn't.

That doesn't stop terminals from supporting it of course, just from saying they do.